As a Los Angeles county prosecutor, Vincent Bugliosi batted a thousand in murder cases: 21 trials, 21 convictions, including the Charles Manson case in 1971. As an author, Mr. Bugliosi has written three No. 1 best sellers and won three Edgar Allan Poe awards, the top honor for crime writers. More than 30 years ago he co-wrote the best seller “Helter Skelter,” about the Manson case. So Mr. Bugliosi could be forgiven for perhaps thinking that a new book would generate considerable interest, among reviewers and on the broadcast talk-show circuit. But if he thought that, he would have been...