Part of the Casswiki article series Books
Tertium Organum: The Third Canon of Thought, a Key to the Enigmas of the World is a a book by P. D. Ouspensky, originally published in 1912.
This book is Ouspensky’s philosophical and metaphysical synthesis, written before his time with G.I. Gurdjieff. It contains a great deal of interesting material, some of it referred to in [[The Wave Series|The Wave]].
This book is available as a free PDF download or can be read on Sacred Texts.