Daniel Geoffrey Homes Mainwaring, a prolific novelist and screenwriter, spent most of his long career in Hollywood working on "B" films and independent productions. Although he helped to write more than forty scripts in twenty-five years, Mainwaring's major work spanned a ten-year period, beginning with Out of the Past (1947), and including The Lawless (1950), The Phenix City Story (1955), and Invasion of the Body Snatchers (1956). He wrote several Westerns and two science fiction scripts but seemed most comfortable in the crime genre, reflecting his background as a crime reporter and mystery writer.

Mainwaring was born in Oakland, California, and grew up on a family farm in the Sierra Nevadas. After graduating from Fresno State Teachers College and teaching briefly, Mainwaring worked as a journalist for several New York dailies before returning to California as a crime reporter for the Los Angeles Examiner.

One Against the Earth, Mainwaring's first novel, was...