Dr. Sherman Hershfield woke up one morning and was surprised to find himself behind the wheel of his car. Somewhere between his Beverly Hills apartment and his practice in the San Fernando Valley, the silver-haired physician had blacked out. Somehow, he’d avoided a crash, but this wasn’t the first time. “I didn’t know what was going on,” he admitted.

Apart from his frequent blackouts, Hershfield was in fine health for a man in his 50s. He was tall and lean, ran six miles a day, and was a strict vegetarian. “I believe a physician should provide exemplary motivation to patients,” he once wrote. “I don’t smoke and have cut out all alcohol.” Hershfield specialized in physical medicine and rehabilitation, and for decades had helped patients with brain injuries learn to walk again and rebuild their lives. Even with his experience, Hershfield didn’t know what was wrong inside his own head.

Perhaps the mystery blackouts were caused by stress, he wondered. Hershfield was the medical director of the rehab center at the San Bernardino Community Hospital, but he also ran a private practice 76 miles away in Winnetka, offering non-surgical spinal treatments. “Sometimes I worked from 6 a.m. to 3 a.m.,” he recalled, adding that the pressures had cost him his first marriage. At the hospital, Hershfield often slept in the doctor’s lounge, where colleagues nicknamed him “Dr. Columbo” after the disheveled television detective.

Not long after the blackouts started, Hershfield suffered a grand mal seizure—the type most people imagine when they think about seizures. He was driven to the emergency room, thrashing and writhing like a 6-feet-4-inch fish pulled out of the water. Concerned doctors at the UCLA Medical Center rushed him into an MRI machine, and, this being the late 1980s, wondered whether he might have pricked himself with a needle, and contracted AIDS. Instead, the scan revealed that his blackouts where actually a swarm of small strokes, and his illness was diagnosed as antiphospholipid syndrome. Hershfield’s immune system was mistakenly creating antibodies that made his blood more likely to clot. Those clots, if they entered his bloodstream and brain, could kill him at any moment.

Doctors prescribed blood-thinning medication and forced Hershfield to quit driving, but he was still fit to practice medicine. Like many survivors of stroke, his speech became slurred and he sometimes stuttered. His personality also seemed to change. He suddenly became obsessed with reading and writing poetry. Soon, Hershfield’s friends noticed another unusual side effect: He couldn’t stop speaking in rhyme. He finished everyday sentences with rhyming couplets, like “Now I have to ride the bus, it’s enough to make me cuss.” And curiously, whenever he rhymed, his speech impediments disappeared.

A STROKE or “brain attack” can happen to any of us at any time. One occurs every 40 seconds in the United States, and they can lead to permanent disability and extraordinary side effects. Some patients become hypersexual or compulsive gamblers. Others have even woken up speaking in a fake Chinese accent. “There was a famous guy in Italy who had what they called ‘Pinocchio syndrome,’” said Dr. Alice Flaherty, a joint associate professor of neurology and psychiatry at Harvard Medical School. “When he told a lie he would have a seizure. He was crippled as a businessman.”

One of Dr. Flaherty’s most famous cases was Tommy McHugh, a 51-year-old British man who suffered a subarachnoid hemorrhage—a stroke caused by bleeding around the brain. Once a grizzled ex-con, McHugh’s stroke changed his entire personality. He became deeply philosophical, and spent 19 hours a day reading poetry, speaking in rhyme, painting, and drawing. He’d never been inside an art gallery before, he joked, “except to maybe steal something.”

For Hershfield, a love of poetry was also completely out of keeping with anything in his past. He was born in Winnipeg, Canada, in 1936, and while his mother was a concert pianist, he followed his father into medical school, graduating in 1960. In Flin Flon, a Canadian mining city, he mended the heads of injured hockey players, then became a resident at the University of Minnesota, before serving in the U.S. Army Medical Corps. In 1973, he arrived in Southern California and set up his practice, where he had little time for reading anything but medical journals.

His problems started during the medical malpractice crisis in the 1970s. Lawsuits against doctors became popular, and the cost of Hershfield’s liability insurance rose from $864 to $3,420. In protest, he quit working all but emergency cases, and took a job frying fish at Thousand Oaks Fish and Chips for $2 an hour. Newspapers across America wrote about the doctor who fried fish while wearing hospital scrubs, adding that Hershfield “looked like he was about to have four cod fillets wheeled into surgery. He explained: “I’ve always been a person of high moral values. I’ve thought, what the hell do I want out of life? And it comes out, I want to be happy.”

Hershfield did return to medicine, but things went from bad to worse when his business partner and best friend started to abuse drugs. “He was an excellent surgeon, a handsome man who had everything going for him ... but he was unable to control his fears and constant bouts of withdrawal and depression, and he tried five times to take his life,” he recalled. Hershfield was there when his friend’s heart finally stopped, after six days on a respirator.

By 1987 he’d filed for bankruptcy. A year later he became the medical director at the rehab center, where he butted heads with management over his “odd” ideas, like opening a hospice where pets could stay with their dying owners. That was around the time the blackouts started.

In the 10 years following his stroke, Hershfield dedicated his free time to a Buddhist organization called Soka Gakkai International, where he loved to chant for hours. He had met his second wife there, Michiko, a beautiful Japanese divorcée who he impressed with his intellect, and his three medical certificates. Michiko told me that her husband “changed a lot,” following his stroke. “He used to like Japanese haiku poems, you know, five, seven, five.”

Hershfield also embraced his Jewish heritage, and volunteered at the Simon Wiesenthal Center, a Jewish global human rights organization. “I did the Holocaust in rhyme,” he recalled of the educational poem he’d perform on the bus. The city now sounded like a swinging rhythm section: Brakes hissed. Horns honked. Passengers rang the bell. As Hershfield recited his rhymes alone, he had become just another crazy person talking to himself on public transport. Then, one afternoon, as he waited at a bus stop in Hollywood, a man selling jewelry overheard him and suggested that he take his lyrics to Leimert Park.

“Where is Leimert Park?’” Hershfield asked. He had never been there.

Intrigued, he rode a bus headed into South Central, past Crenshaw’s Magic Johnson theater, the neighborhood’s megachurches, and liquor stores. At the foot of Baldwin Hills he found it—an area with one of the largest African-American populations in the western United States. If Leimert Park was 100 people, just one was white.

Since the 1960s, Leimert Park had been the center of African-American culture in Los Angeles—Duke Ellington, Ella Fitzgerald, Miles Davis, Ray Charles, and Richard Pryor had all lived within five miles of the place. To outsiders, it was known only as a hotspot during the Los Angeles riots in 1992. The jazz poet Kamau Daoud told me that locals still refer to the riot as “the rebellion.” The village would not quickly forget the four white police officers who beat the black motorist Rodney King half to death.

It was the very late 1990s when Hershfield stepped off the bus, dressed like a doctor who lived in Beverly Hills. He walked in polished shoes to the beat of the drum circle that gathered in the park, past the row of Afrocentric bookstores and shops selling colorful fabrics, where saxophone music leaked from every door and window. At 43rd and Leimert, he found a crowd of teenagers surrounding a community arts center called the “KAOS Network.” This had to be it: Spontaneous rap battles were breaking out, and dancers writhed on the sidewalk, seizurelike. At the entrance, a young man sized him up.

“Would you like to hear something?” Hershfield asked politely.

“Sure, what’s your name?” the man asked.

Hershfield looked at him.

“My name is Dr. Rapp.”

ESTABLISHED IN 1984 as a media-production center, KAOS Network was famous for “Project Blowed,” an open-mic workshop for up-and-coming rappers. Since 1995, the project had turned the dance floor into a living Venn diagram of performers from various gang-controlled neighborhoods, mostly African-American teenagers wearing baggy pants, Timberland boots, and caps pulled down just above the eyes.

“It was underground, powerful, strong, and scary for people if they weren’t ready, because it was really volatile,” explained the proprietor, Ben Caldwell, a 73-year-old African-American filmmaker with a tidy, graying beard. “I would have to take a deep breath every time, because it was a bunch of alpha males.” The project was a tough breeding ground for rappers, who hoped to “blow up,” like the underground performer Aceyalone, or more mainstream stars like Jurassic 5. But Hershfield knew nothing about any of this.

“He said he wanted to do a rhyme on the Holocaust,” Caldwell remembered. “I thought that was really insightful. I thought that it would be something good for the kids to hear.” This was unusual, but not against “da mutha f**ckin rulz” pinned to the door, that began: “PROJECT BLOWED IS PRESENTED FOR THE LOVE OF HIP-HOP ENTIRELY FOR BLACK PEOPLE.” The sign continued: “DO NOT GET VIOLENT BECAUSE THIS IS A BLACK-OWNED, BLACK-OPERATED BUSINESS.”

The entrance fee was $2 to perform, $4 to watch, and rappers were expected to “perform a polished piece of music,” wrote Jooyoung Lee in Blowin’ Up, a history of the club, adding: “The open mic is a lot like peer review.” Emcees with the skill to rap spontaneously—“freestyling”—enjoy the greatest respect. But when a rapper forgets his lines, stutters, or shows up unprepared, the crowd forces them offstage with a devastating chant:

“Please pass the mic!”

The DJ demanded Hershfield’s backing music. He handed over a cassette tape of Chopin. Piano music filled the room. Regulars in the audience, known as “Blowdians,” looked at each other.

“They all were going, ‘Uh hunh, uh hunh,’” Hershfield recalled, but they quickly tired of the classical music.

“Okay,” someone said. “Get rid of that music and let’s hear you rap.”

Alone on the stage, Hershfield gripped the mic, and began:

“God, this is a tough thing to write

The feeling I got in my heart tonight

Just to think of the Holocaust

So deep and sadly blue

And still so many people

Don’t think it’s true.”

The crowd was silent. Here was an old man, reading a poem.

“The first time he was up there, he wasn’t that successful,” Caldwell said. But out of respect, the audience didn’t chant him off. Project Blowed calls itself the longest-running open-mic session in the world, and they’d never seen anyone like Hershfield on stage. “First of all, he’s Caucasian around all these people of color,” said one regular, called Babu. “I thought he was some kind of spy.” Hershfield was also the oldest person in the room: “If you up in your mid-thirties and still ain’t got it,” a Blowdian called Trenseta would say, “Leave hip-hop alone, and go get you a little job at International House of Pancakes or some shit!” Hershfield was now 63, a dinosaur in rap years.

Clarence Williams / LA Times

As he emerged into the hot South Central night, Hershfield heard a voice from Fifth Street Dicks, the neighboring coffee shop: “If you can’t keep up with those kids, then you’d better do something else,” shouted Richard Fulton, a large man with graying dreadlocks. Fulton’s jazz cafe was a hotbed of African-American writers and artists, and he’d seen many beat poets try their luck in Leimert Park—none of them from 90210, America’s ritziest zip code. “At that time I thought I was rapping,” Hershfield later recalled. “I wasn’t rapping, I was just reading poetry. It didn’t have any beat. When you’re on rap street, you gotta have that beat.”

Undeterred, Hershfield put aside his Tchaikovsky records and listened to NWA and Run-DMC. He played rap music in the bath, Michiko told me. When she found out he was preparing for rap battles in South Central, she told him: “You’re crazy!” But she couldn’t stop him returning to Project Blowed every week, sometimes making the six-and-a-half mile journey from Beverly Hills on foot.

“Sherman’s leaving at 10 o’clock at night and going to Crenshaw,” she told her son, Scott. “He’s hanging out with kids and rapping.” Scott, who had transitioned from a teenaged professional skateboarder into a hip-hop DJ, was now in his 20s and was scoring regular gigs at Hollywood’s celebrity-filled clubs. When he saw his stepfather rapping at home, he felt embarrassed.

“Sherman, you’re kinda just rhyming, putting words together, but you know so many Latin words, you should rap about neurology, really get into the science of it ... that would be amazing,” he said. Scott encouraged his stepfather to be more like the hip-hop rappers he admired. “Even though I’m from the West Coast, most of the stuff I really liked was East Coast 90s hip-hop ... I was into KRS-One.”

In the mid-1980s, KRS-One had emerged from the Bronx as the emcee of Boogie Down Productions, with the seminal album Criminal Minded. As a solo artist he’d created one of hip-hop’s most enduring records, Sound of Da Police, and was now a leading rap scholar and lecturer. One evening in October 1999, Hershfield heard that KRS-One was speaking about rap history at an event for hip-hoppers in Hollywood, and decided to swing by. “Try to imagine a hip-hop gathering,” KRS-One told me, late last year. “You know, emcees from the hood, breakers, DJs, music is blasting. I’m giving you permission to stereotype. Then in walks this dude.” It was like Larry David had wandered into a Snoop Dogg music video.

During the Q&A, Hershfield grabbed the mic and started to tell his story.

He explained that he was getting his language back together after a stroke by listening to rap records. “One of which was one of my songs,” KRS-One recalled.

Hershfield couldn’t stop himself.

“I started to have a stroke,” he rapped. “Went broke.”

The room fell silent.

“I started to think and speak in rhyme. I can do it all the time. And I want to get to do the rap, and I won’t take any more of this crap.”

The crowd erupted.

When Hershfield rapped about his struggles, not history lessons, he inspired the audience.

“He got a standing ovation,” recalled KRS-One. He gave the doctor his telephone number and suggested they hang out.

“I didn’t know anything about him,” Hershfield recalled. “I just knew that he was in the same category as Tupac Shakur.” When Hershfield told his stepson about his new friend, Scott was stunned. “You know, you should really listen to his music and listen to his lyrics,” he told his stepfather. But inside, Scott was thinking: Let’s see how long this lasts. KRS-One?

A few days later, the rap icon arrived at Hershfield’s office. KRS-One gave the doctor a signed copy of his book, The Science of Rap. He too was fascinated with neurology, he said: “I was already talking about the concept of how rapping synthesizes those two hemispheres of the brain,” KRS-One told me. He asked Hershfield if he’d like to be part of an experiment, and offered him rap lessons.

“When you’re trying to teach someone to rap, you ask them to sing along with a song they might have heard,” KRS-One told me. He hit play on Rapper’s Delight by the Sugar Hill Gang. The song began:

“I said a hip-hop / Hippie to the hippie / The hip, hip a hop, and you don’t stop ...”

Then he pressed rewind and encouraged Hershfield to give it a try.

“He nailed it,” said KRS-One.

“He had the cadences and the rhythms,” he added. But the doctor needed to work on his delivery, breath control, and enunciation. And so an unlikely friendship blossomed between the Blastmaster and the Buddhist. They were both interested in spirituality: The rapper’s name, ‘KRS,’ came from the Hare Krishna volunteers he befriended in a youth spent on the streets of the Bronx. And just as Hershfield had lost his business partner to suicide, KRS-One had lost his right-hand man, DJ Scott La Rock, who was shot in 1987. The loss was life-changing for the rapper: his lyrics became more political and philosophical; he launched a movement called Stop the Violence.

To KRS-One, Hershfield was a pioneer of rap theory. “He was talking about neuroplasticity before I heard about it on PBS,” KRS-One recalled.

KRS-One suggested they write a book together, or record an album in New York.

He told the doctor: “I visualize you as revolutionizing hip-hop.”

HERSHFIELD RETURNED to Project Blowed, where he vowed to win over the crowd. The elder statesmen of Leimert Park took Hershfield under their wing, making sure he got time on the mic, and that he got home safe. “People respected him and he could work on his chops, work on his brain,” Caldwell told me. “It was interesting to see how well we all accepted him.” Caldwell encouraged Hershfield to experiment. “He wanted to do Jewish chants,” he recalled. “And I was like ‘That is so fucking tight.’”

The younger members of Project Blowed were also drawn to Hershfield. Up-and-coming rappers in South Central suffered from an “existential urgency,” Lee wrote in Blowin’ Up. Theirs was a race to “make it” in hip-hop, before their life was derailed by gang violence. Like them, Hershfield was rapping against the clock, unsure when the next seizure might strike.

Richard Fulton, the coffee shop owner, became especially close with Hershfield. Fulton was a cancer survivor and former drug addict, who had once pushed a shopping cart along Skid Row’s 5th Street. That was before he found God—and jazz. Against all odds, a reborn Fulton launched his coffee-and-music operation. His caffeine was strong and the jazz loud. Like Hershfield, Fulton’s second life was dominated by a love for music. His catchphrase was “Turn the music up.”

Hershfield and Fulton were kindred spirits, said Erin Kaplan, a journalist who frequented Leimert Park. Both men were enjoying “second chances,” she explained, and living “on borrowed time.” Hanging out at Dick’s, Hershfield brushed shoulders with beat poets, rappers, chess players, and jazz musicians. It was there he fell into the rhythm of Leimert Park.

Every week for two or three years, Hershfield climbed onstage at Project Blowed and gave his everything, sweat on his brow, steam on his glasses, fists pumping. Sometimes he electrified the crowd, other times: “Please pass the mic!” He learned to self-promote and name-check “Dr. Rapp” in his lyrics just like the pros; he wore customized T-shirts and learned to freestyle. He performed on the stage and in impromptu “ciphers” under street lamps, until the sun came up.

“He was tight,” the rapper Myka 9 told me, while he smoked in an alleyway before a performance in Culver City. “He had a little bit of an angular approach. He had flows, he had good lines that were thought out, I remember a couple punchlines that came off pretty cool.” Myka 9 recalled socializing with Hershfield at house parties in South Central, and described him as “a cult personality in his own right.”

At home, the doctor’s wife was worried. “I don’t understand why he goes to that area,” Michiko told me. Her husband was too generous and trusting, she added. “I bought him nice clothes, Italian-made suits, a couple times he came back with dirty clothes, he’d given the nice suit to somebody else.” With his designer threads and prescription pad, Hershfield was a mugger’s dream.

“I keep telling him it’s dangerous,” Michiko told me.

Hershfield insisted he was safe. These people were his friends, he said.

NOT EVERYONE IN the world of hip-hop was enthused by Hershfield. A letter arrived from a lawyer representing a different Dr. Rap, who advised him to find a new name or face legal action. Hershfield, who actually had a doctoral degree, rebranded to Dr. Flow, but it was too late. His reputation was spreading.

In early 2000, Hershfield attended a talk about violence and rap music at the California State University at Los Angeles. Sitting on the panel was one of Gangsta Rap’s pioneers, Ice-T, who argued that violence was an unavoidable part of rap culture. “I’m a person who deals with violence always in my music,” he told the audience. “Masculinity runs this world. The person who’s violent gets control. Peace gets nothing.”

Hershfield was infuriated.

“You can’t live by hate!” he yelled out, before trading comments with Ice-T in an ugly scene that required the moderator’s intervention.

Hershfield was appalled by gang violence and its needless killings. Internally, he was struggling with the fragility of his existence: He had survived a deadly stroke, and life was a precious gift.

No one was more devastated than Hershfield when Fifth Street Dick’s cancer returned. Hershfield was one of the many Leimert Park regulars who surrounded Fulton’s bedside. He found his friend unable to speak, the tumor in his throat so large that his tongue protruded from his mouth. Fulton could only communicate by writing notes, and knew his life was ebbing away. But Hershfield couldn’t accept it.

“If I can just get him to chant, he’ll recover,” Hershfield said, as decades of medical experience were drowned out by denial.

He started his Buddhist chant:

“Nam-myoho-renge-kyo.”

Friends urged Hershfield to stop, but he wouldn’t listen. Fulton, 56, could barely breathe, let alone speak.

“We’re going to tap into his life force,” Hershfield insisted.

But on March 18, 2000, jazz filled Fulton’s room as he declined a final morphine shot, and instead told nurses in a note: “Turn the music up.”

Back at Project Blowed, Hershfield intensified his efforts to dominate the mic. But his double life soon became strained, as his two worlds splintered. “His friends in Beverly Hills did not approve of this at all,” said Kaplan, Hershfield’s journalist friend. “They were so shocked. Let’s just say none of his friends showed up at open-mic night.” By choosing rap nights instead of night shifts, Hershfield soon fell into another financial crisis. “I think he was more obsessed with rapping than he was going to work,” his stepson Scott told me. Sometimes, Michiko told me, the guys from Leimert Park would lend Hershfield money for the bus.

Soon, Hershfield’s voice became hoarse from shouting rhymes over African drums, and staying out all night. Then, during one particularly hot evening, everything went black. “Dr. Rapp had a seizure,” recalled Tasha Wiggins, who worked for KAOS Network. “Other rappers caught him. Everybody stopped what they were doing, trying to nurture Dr. Rapp.” As Hershfield lay unconscious on the floor, the crowd started chanting his name.

THOSE WHO HAVE been struck by the strange side effects of brain injuries often speak of their gratitude. Just before he died of cancer, Tommy McHugh, the British convict who became an artist, said his strokes were “the most wonderful thing that happened.” He added that they gave him “11 years of a magnificent adventure that nobody could have expected.” Dr. Flaherty described McHugh’s hemorrhage as “a crack that let the light in.” McHugh and Hershfield both experienced symptoms of what the physician and author Oliver Sacks called “sudden musicophilia,” an eruption of creativity following a brain injury or stroke. But for Hershfield, rhyming was no longer a symptom, but a cure.

It was as if one side of Hershfield’s brain that held the rhymes healed the broken side that had short-circuited. Brain scans on rappers carried out by the National Institute on Deafness and Other Communication Disorders (NIDCD) discovered that during freestyle rapping, brain activity increased in the brain areas that engage motivation, language, mood, and action. Hershfield said rapping kept his seizures under control, and even after he collapsed that night in Leimert Park, he used hip-hop to regain his speech and return to the stage.

Soon, Dr. Rapp’s notices at Project Blowed started improving.

“His name was on the lips of the multitudes,” recalled Ed Boyer, a Los Angeles Times journalist who first heard rumors about South Central’s rapping doctor in April of 2000. Boyer tracked down Hershfield to his office, and visited Project Blowed to hear him perform. “I’ve seen Dr. Rapp rock the whole house,” Tasha Wiggins told Boyer, as Hershfield climbed onto the stage. Another Project Blowed member, Gabriela Orozco, said, “Oh, I think I’m going to cry. I mean ... he’s doing it.”

As Dr. Rapp stepped into the spotlight and the DJ’s needle found the groove, he became lost in his rhymes:

“Me, I’m just a beginning medical intern of rap

Trying to express and open my trap ... ”

Hershfield’s stepson, Scott, remembers the morning he opened the Times and saw a photograph of Dr. Rapp, wearing an Adidas tracksuit, mid-flow, on the paper’s Metro pages. “The whole thing was so bizarre,” he said.

Dr. Rapp had finally “blown up.”

RADIO AND TELEVISION crews from Canada and England soon descended on Leimert Park looking for Hershfield. Ben Caldwell showed me footage from a Japanese television station, who filmed Hershfield waiting to take the mic. He looked like a retiree standing in line for an early bird dinner special. Then he laid down his rhymes, as the crowd bobbed their heads in appreciation. Afterwards Hershfield took a nap on a couch. “He did that quite regularly,” Caldwell sighed. “Everybody liked the doctor, right, even the hardcore gangster types,” he added. “They liked him for his chutzpah.”

Hershfield told reporters that Leimert Park had opened his eyes to a whole new world. “There are lots of misconceptions by white people about the area,” he said. “It’s very cultural with a lot of interesting places.” Project Blowed was “the Harvard of rap,” he said. “This is my foundation. I find it very beneficial.”

Though he never recorded an album with KRS-One, Hershfield owed his underground rap career to the Blastmaster. KRS-One, who now lives in Topanga Canyon, California, told me: “He mentioned one of my songs brought him back. He was in a coma, they were playing music for him to try and wake him up.” He added: “I’ve met a lot of people, but a few people I will never forget. [Hershfield] saying rap healed him ... that just stayed with me ... It’s part of my confidence in hip-hop.”

Instead of embarking on a world tour, Dr. Rapp continued to pay his dues at Project Blowed every week. Like a true underground star, he shunned mainstream success. He did appear in a documentary about Leimert Park, not as a novelty act, but as a regular member of the crew. “I can’t clearly tell you whether [rap] helped him,” said Michiko, “but I can tell you he was happy when he was doing rap music.” Hershfield represented Project Blowed until ill health forced him to quit both music and medicine. He died from cancer in Los Angeles, on March 29, 2013, aged 76.

Today, Project Blowed lives on, every third Tuesday at KAOS Network in Leimert Park. The area remains the “hippest corner in Los Angeles”—according to the recording on the club’s answering machine. But Leimert Park is now fighting a new battle, against soaring property prices and gentrification. The reason Hershfield was accepted at Project Blowed, said Caldwell, was that he arrived with an open mind, and he listened and learned. “That’s one wonderful thing I like most about black American communities,” he said. “As long as you don’t try to tell them how to do their own culture, you’re good.” Ever since Dr. Rapp’s days, performers from all races and backgrounds have jumped onstage, added Caldwell. But the moment they stutter or slur, it’s always the same:

“Please pass the mic.”