Zodiac is a 2007 American mystery thriller film directed by David Fincher from a screenplay by James Vanderbilt, based on the 1986 non-fiction book of the same title by Robert Graysmith. The film stars Jake Gyllenhaal, Mark Ruffalo, and Robert Downey Jr. with Anthony Edwards, Brian Cox, Elias Koteas, Donal Logue, John Carroll Lynch, Chloë Sevigny, Philip Baker Hall and Dermot Mulroney in supporting roles.