This book is the Dark Lords' study of Chaos-the formless, uncontrollable force from outside the ordered Cosmos that sorcerers, mystics and warriors have always spoken of and sought power in. We discuss all aspects of this phenomenon: its metaphysics, mythology, philosophy, psychology and symbology, and its applications to sorcery, demonology, warfare, religion and cult creation. Far more than an academic study, this work is a call to take sides in the great metaphysical war that has been waging from time immemorial: the Chaoskampf and the Ordnungkampf-the holy wars against Chaos and Order. We provide the reader an in-depth foundation in Chaoism-the ideology for the Chaos sorcerer and warrior who seeks unlimited power and purpose by advancing Chaos upon this plane. For those who wish to live by the creed of "nothing is true and everything is permitted"; who feel called to fight a holy war for the eight-armed cross of Chaos; who perceive that an old age of Order is succumbing to a new age of Chaos; who seek a path of power and glory through the rising tide of Chaos: let this book your guide. To you we say: Klân-râk âm chod! (Chaos power to you!) Dark Lords Kârzathor & Ravuk, Dark Lords of Chaos, Year 9 of the Imperium.