"A light appears in the darkness but heed my warning. The path is long and uncertain. There is no turning back. No expense may be spared. You must overcome your fears and delusions and lay claim to a terrible strength. Then you may unlock what is closed and enter the gates of Babylon." This book, philsophical companion to The Book of Infernal Prayer, is for those seekers who wish to better understand the crooked path they have found themselves compelled to tread. Where The Book of Infernal Prayer provided the praxis, The Nine Gates provides the theory.