The greatest of psychologists, wundt, has written a series of lectures on psychology (lately translated into English), but the style and the matter are fully intelligible only to those who are already somewhat familiar with the science. No one else has produced a book explaining the methods and results of the new psychology. This is my reason for writing one. This is the first book on the new, or experimental, psychology written in the English language. That it has been written expressly for the people will, I hope, be taken as evidence of the attitude of the science in its desire to serve humanity.