An American science fiction author of over forty books, he is known for his Forge of God series, which centers around a large-scale galactic conflict. His other popular works include Queen of Angels (1990), Blood Music (1983), and The Way series (1985-1999).
He studied at San Diego State University. He published his first novel, Hegira, in 1979.
He worked as an illustrator early in his career.
He married Astrid Anderson in 1983; together, they had two children.
He wrote a series of prequel novels to Isaac Asimov's Foundation trilogy.