Shadows abound in The Leopard Man, the third of the Val Lewton-Jacques Tourneur collaborations. While Leopard does not quite compare to the previous two (Cat People and I Walked with a Zombie), it is nonetheless a gripping and exciting psychological thriller. Tourneur knew that exploring the human mind and the human psyche -- if there is a difference between them -- involves digging through many layers of darkness, and Leopard is filled with eerie shadows and with shades of gray and black that can be startlingly ferocious. Working from Edward Dein's taut adaptation of the wonderful Cornell Woolrich novel, Tourneur creates a mesmerizing world in which questions abound and those who presume certainty in their answers are only fooling themselves. The director wraps the story in ambiguity and in so doing offers a glimpse at the terrifying underside of both nature and humanity. He is enormously helped by Robert de Grasse's brilliant cinematography, the instrument that fully realizes Tourneur's vision. Also of note is the intriguing Roy Webb musical score, which is invaluable in establishing atmosphere and suspense. Of the cast, Dennis O'Keefe and Jean Brooks are a bit weak; they're not bad, just not as strong as one wishes. But Margo is in quite good form.