From the New York Times Book Review:
As early as 1970 Ali’s physician Ferdie Pacheco (the “Fight Doctor”) began numbing Ali’s fists before fights with cortisone and an anesthetic called Xylazine. “Ali’s hands were so shot he couldn’t hit a pillow,” Ali’s business manager said. It was suspected by his handlers that Ali had incurred “lasting brain damage after the Frazier fight in 1971,” but his final fight, a shameful debacle in which he could scarcely defend himself against the much younger Trevor Berbick, was in 1981…
Asked why he’d continued to work with Ali despite his diminishing skills, Ferdie Pacheco replied angrily: “You’re in the corner to keep them fighting … not to tell them not to fight. If you didn’t tell them to fight, you were fired immediately.” Ali’s famous “rope-a-dope” strategy, which allowed him to win the Rumble in the Jungle against the younger, stronger George Foreman by absorbing as many powerful blows as Foreman could throw, was in the short run a triumph; in the long run, a medical disaster. The later years of Ali’s decline are depicted in chapters in Eig’s biography with such ominous titles as “‘They May Not Let Me Quit,’” “Staggered,” “Old,” “The Last Hurrah” and “Too Many Punches” that take us 18 years beyond the brightly lit terrain of Remnick’s biography into a hellish twilight of irreversible neurological damage…
“Some writers said that Ali had ‘transcended’ race. It was an attempt to whitewash his legacy, and it was dead wrong. Race was the theme of Ali’s life.”
Ali was illiterate and had an IQ of about 78.