The guiding spirit of the philosophical engagement of Bertrand Russell was to outline a scientific philosophy with the intention of introducing progress and continuity in the subject. With this aim in view, he developed the analytic method which has inspired one of the most influential philosophical currents of this century. Russell's confidence was confirmed by the result of his analysis of perception and physics. This book examines three different theories that Russell used in an effort to provide a lasting solution to the problem of perception and its relation with the external world. Despite the merits of Russell's attempts, the author is convinced that Russell failed to achieve his aim, but that his failure points the way to a better understanding of the nature and purpose of philosophy.