The first interview for his previous book, about Muhammad Ali, was even rockier. The late Ferdie Pacheco, Ali's doctor and cornerman, "just screamed at me," he said. "He called me an idiot.

The first interview for his previous book, about Muhammad Ali, was even rockier. The late Ferdie Pacheco, Ali's doctor and cornerman, "just screamed at me," he said. "He called me an idiot. He ...