> [!info] Part of the Casswiki article series [[Books]] ![[TertiumOrganum.png|hsmall center]] > [!caption|center no-title no-icon no-margin ] > _Tertium Organum_, 1970 Edition _**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 [[George Gurdjieff|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](tertiumorganumth00uspe.pdf) or can be read on [Sacred Texts](http://www.sacred-texts.com/eso/to/). See also -------- * [[The Wave Series]] * [[P. D. Ouspensky]]