In preparing the following abridgment of my larger work, the Principles of Psychology, my chief aim has been to make it more directly available for class-room use. For this purpose I have omitted several whole chapters and rewritten others. I have left out all the polemical and historical matter, all the metaphysical discussions and purely speculative passages, most of the quotations, all the book-references, and (I trust) all the impertinences, of the larger work, leaving to the teacher the choice of orally restoring as much of this material as may seem to him good, along with his own remarks on the topics successively studied. Knowing how ignorant the average student is of physiology, I have added brief chapters on the various senses. In this shorter work the general point of view, which I have adopted as that of natural science has, I imagine, gained in clearness by its extrication from so much critical matter and it's more simple and dogmatic statement. About two fifths of the volume is either new or rewritten, the rest is scissors and paste. I regret to have been unable to supply chapters on pleasure and pain, aesthetics, and the moral sense. Possibly the defect may be made up in a later edition, if such a thing should ever I be demanded.