Daniel Keyes’ book about Billy Milligan (1981), who suffered from dissociative identity disorder, is now considered a classic on the subject. Keyes faithfully and compellingly recounts the life of Billy Milligan, who gained notoriety in the 1970s. For anyone curious about multiple personalities and wondering how on earth so many different identities can coexist within a single person, this book is a must-read!

The Minds of Billy Milligan: A Non-Fiction Book with the Potential of a Novel
Keyes did not artificially dramatize Billy Milligan’s story but instead aimed to tell it as authentically as possible. He conducted months of interviews with Billy, and when Billy eventually fused into a single personality known as The Professor, the author was finally able to gain full insight into his life. The Professor remembered everything that the various personalities had done. This led to Keyes’ book, which at times reads like a novel—gripping, entertaining, and enlightening!
Before I started reading, one question had been lingering in my mind: “How on earth is it possible for so many different personalities to exist within one person?” By the time I finished the last page, I had my answer: traumatic experiences combined with intelligence and the vast, unfathomable potential of the human mind made it possible. Naturally, Billy encountered many people in his life who dismissed him as a fraud or a manipulator. But thanks to courageous psychiatrists who fought for him and the truth, he was finally able to receive treatment.
What Billy experienced throughout his childhood, youth, and adulthood—despite his condition—is truly incredible (abusive stepfathers, armed robberies, drug smuggling, a love story, unexpected journeys, and more). Equally astonishing were the distinct abilities of his different personalities. Tommy (16 years old) was highly skilled with his hands and could escape almost any situation. Ragen Vadascovinich (23) was incredibly strong, proficient with weapons, and even spoke fluent Serbian-Croatian. Danny (14) was a timid boy with a talent for drawing. Adalana (19) was an introverted lesbian responsible for cooking. Kevin (20) was a petty criminal involved in several robberies. And the list goes on—an incredible diversity existed within Billy!
Keyes’ The Minds of Billy Milligan ends in 1981 with Billy’s admission to an unpredictable institution in Lima, Ohio, where he was denied the proper treatment for dissociative identity disorder…
A Hollywood Biopic?
Once you learn about Billy Milligan’s turbulent life and his many personalities, it’s no surprise that Hollywood has attempted multiple times to adapt Keyes’ book and Milligan’s story for the screen. Over the years, filmmakers such as James Cameron, Joel Schumacher, and David Fincher were all linked to the project. In 2015, a more concrete adaptation was in development, with Leonardo DiCaprio set to portray Billy Milligan. It wasn’t until 2023 that The Crowded Room, a miniseries by Akiva Goldsman starring Tom Holland and Amanda Seyfried, was finally released. The 10-episode series premiered on Apple TV+.
However, the first filmmaker to tackle the essence of Milligan’s story was M. Night Shyamalan (The Sixth Sense, 1999). Rather than directly adapting Milligan’s life, Shyamalan drew heavy inspiration from it to create an entirely new and original work. This resulted in Split (2016), a film that became a worldwide phenomenon and sparked intense debate. Like Billy Milligan, the character Kevin Wendell Crumb possesses 24 personalities—though instead of a wise and benevolent Professor, the 24th identity is an all-powerful, vengeful Beast…
What Happened to Billy Milligan?
Billy Milligan’s tragic story did not end with Daniel Keyes’ book. After spending nearly a decade in psychiatric institutions—facing both supportive and hostile psychiatrists—Billy was eventually released in the early 1990s. He later lived in California, where he founded Stormy Life Productions and planned to direct a short film, though the project never materialized.
Billy passed away in 2014 at the age of 59 from cancer, which once again drew media attention, including coverage in the Los Angeles Times (Billy Milligan dies at 59; first to use multiple personality defense). Coincidentally, Daniel Keyes, the author of his biography, also passed away in 2014.
For anyone wanting to learn more about dissociative identity disorder (DID) and move beyond clichés, reading Keyes’ The Minds of Billy Milligan and delving into Billy Milligan’s fascinating yet heartbreaking life is highly recommended!