All cities have their secrets, but none are so dark as San Francisco's, the city that Ambrose Bierce famously described as "a point upon a map of fog." With its reputation as a shadowy land of easy vice and hard virtue, San Francisco provided the ideal setting for many of the greatest film noirs, from classics like "The Maltese Falcon" and "Dark Passage" to obscure treasures like "Woman on the Run" and "D.O.A.", and neo-noirs like "Point Blank" and "The Conversation." In this guide to more than forty film noirs and the locations where they were shot, readers visit the Mission Dolores cemetery, where James Stewart spies Kim Novak visiting Carlotta's grave in "Vertigo"; the Steinhart Aquarium, where Orson Welles and Rita Hayworth rendezvous in "The Lady from Shanghai"; and Kezar Stadium, where Clint Eastwood, in "Dirty Harry," captures the serial killer, Scorpio, in a blaze of ghastly white light.