In the 1980s, Howard Bloom was a fast-talking, headline-making music publicist. But in 1988, he hit a wall. For 15 years, he suffered from chronic fatigue syndrome so severe that he barely got out of bed. “And for five of those years I was too weak to speak and too weak to have another person in the room with me,” Mr. Bloom, now 74, said. Nonetheless, he managed to write three science-related books during those years, and recently published his seventh, “How I Accidentally Started the Sixties,” a memoir of chemical and spiritual experimentation that begins in 1962. Mr. Bloom lives in Park Slope, Brooklyn, where he runs several online discussion groups.