The most talked about episode of The Dick Cavett Show never aired. To this day, that hasn’t stopped hundreds of people from insisting to Cavett that they were watching on June 8, 1971, when guest J. I. Rodale had a heart attack and died onstage while Cavett was engaged in conversation with another guest, Pete Hamill. Rodale was dubbed “the guru of the organic food cult” in a New York Times Magazine profile. During his segment, he boasted, “I am so healthy I expect to live on and on.”

Videotape of the infamous episode exists—but it has never been made public, nor has it been leaked online. Cavett himself has one of the few copies, but only rarely watches it. In a new book, The Show Won’t Go On: The Most Shocking, Bizarre, and Historic Deaths of Performers Onstage, he tells authors Jeff Abraham and Burt Kearns, “About two years ago, my friend Marshall Brickman [the Oscar-winning cowriter of Annie Hall] and I took a mild drink in his New York apartment before loading the disc. We felt the need of something a bit stronger after watching it. The first hour of the 90 minutes is a perfectly good, airable show, with many laughs. The final half hour is hell.”

Ernest Hemingway once said that every true story ends in death. The Show Won’t Go On has scores of true stories about entertainers from all tiers of show business: some that you recognize and some that you’ve probably never heard of, like Sid James, a British character actor best known for his roles in the long-running Carry On films. His last performance was in a play called The Mating Season; he suffered a heart attack in the first act. “He gasped for breath and fell backwards onto a sofa,” the authors write. “The audience laughed. Even the cast thought he was doing it all for show.”

A scriptwriter writing a Sid James biopic would be excoriated for including a scene in which the theater manager informed the show’s producer that James had died in Sunderland, only to be told, “Don’t worry; everybody dies in Sunderland.” But that’s what happened.

Many of the stories Abraham and Kearns relate have similarly ironic punch lines. One of the most famous onstage deaths chronicled belongs to dialect comedian Harry “Parkyakarkas” Einstein, the father of Albert Brooks and Bob “Super Dave” Einstein. In November 1958, he slayed the audience at a Friars testimonial dinner for Desi Arnaz and Lucille Ball, then went back to his seat on the dais and slumped into the lap of Milton Berle. Berle urgently asked if there was a doctor in the house. Singer Tony Martin was pushed to sing something, anything, to distract the crowd. His unfortunate choice of song was “There’s No Tomorrow.”

Both Abraham and Kearns are show business and pop culture savants; the former describes himself as an “entertainment publicist by day and comedy historian by night.” He represented George Carlin during the last 11 years of Carlin’s life, and has also amassed what is allegedly one of the largest comedy record collections in the country: “I have Shecky Greene on speed dial,” he told Vanity Fair.

Abraham and journalist Kearns bonded over a shared love of Jerry Lewis and rock music when Abraham repped Kearns’s 1999 book, Tabloid Baby, which chronicled his stint with the news magazine series A Current Affair and the rise of tabloid television. Kearns has also served as an executive producer on such documentaries as Kardashian: The Man Who Saved O.J. Simpson.