Fictional serial killers are perversely romantic figures, men who have thrown off the shackles of society to pursue their innermost desires, no matter how sick. And judging by the public’s breathless wait for Thomas Harris’ Hannibal, they hold quite an appeal. The real monsters are not nearly so glamorous, but no less fascinating, in the books of John Douglas, the model for The Silence of the Lambs’ Jack Crawford. In The Anatomy of Motive, Douglas and co-author Mark Olshaker insist that there is always a motive, even to the most seemingly “motiveless crime”; understanding this why, combined with the how, leads to whodunnit. Drawing on Douglas’ 25-year career with the FBI’s Investigative Support Unit, the book profiles serial killers, arsonists, bombers, and mass murderers, paying special attention to the factors that help create these often pitiful creatures. However, as Samuel Johnson once said about a violent madman, “We should knock him down first, and pity him afterwards.” Douglas discusses the book at 6 p.m. at the National Museum of American History’s Carmichael Auditorium, 14th & Constitution Ave. NW. $13. For reservations call (202) 357-3030. (Mark W. Sullivan)