An American science fiction author, he is best known for his Eight Worlds series and his Gaea Trilogy. His later works include Dark Lightning, Slow Apocalypse, and the Thunder and Lightning series.
He attended Michigan State University on a scholarship, but dropped out to move to San Francisco, where he worked various odd jobs before dedicating himself to a career in writing.
His works often include prominent female characters, a rarity in the science fiction genre.
He was raised in Fort Worth and Port Arthur, Texas.
He won the Robert Heinlein Award.