Born in Moscow in 1878, Pyotr Demianovich Ouspenskii was a precocious scholar who rejected the chance of academic advancement to travel and write. Ouspensky drew a distinction between commonplace knowledge and what he termed 'important knowledge' the acquisition of which he considered the chief aim of life. Driven by this desire he read avidly, and travelled widely throughout Asia and the Middle East. Ouspensky's own attempts to reach higher states of consciousness convinced him that a third instrument of thought was necessary to liberate humanity from the classical and positivistic modes of thinking that dominated western society (the 'Organon' of Aristotle and the 'Novum Organum' of Bacon). First published in 1922, 'Tertium Organum' ranges brilliantly over a wide swathe of subjects, from Western science through sacred art and symbology to the mysticism of both East and West. Widely regarded as a masterpiece, the work proved an immediate bestseller and established Ouspensky as a major contributor to Twentieth century thought. A fascinating and important book for all those interested in this life's 'important knowledge'.