In naming his book 'Tertium Organum' Ouspensky reveals at a stroke that astounding audacity which characterizes his thought throughout-an audacity which we are accustomed to associate with the Russian mind in all its phases. Such a title says, in effect: 'Here is a book which will reorganize all knowledge. The 'Organon' of Aristotle formulated the laws under which the subject thinks, the 'Novum Organum' of Bacon, the laws under which the object may be known, but 'The Third Canon of Thought' existed before these two, and ignorance of its laws does not justify their violation. 'Tertium Organum' shall guide and govern human thought henceforth.'"-From the Introduction.