Book excerpt: Most film buffs know that Citizen Kane was based on the life of publisher William Randolph Hearst. But few are aware that key characters in films like Double Indemnity, Cool Hand Luke, Jaws, Rain Man, A Few Good Men and Zero Dark Thirty were inspired by actual persons. This survey of a clef characters covers a selection of fictionalized personalities, beginning with the Silent Era. The landmark lawsuit surrounding Rasputin and the Empress (1932) introduced disclaimers in film credits, assuring audiences that characters were not based on real people--even when they were. Entries cover screen incarnations of Wyatt Earp, Al Capone, Bing Crosby, Amelia Earhart, Buster Keaton, Howard Hughes, Janis Joplin and Richard Nixon, along with the inspirations behind perennial favorites like Charlie Chan and Indiana Jones.