This book, by the late Richard Wollheim, is an excellent introduction to Freud's ideas. It traces the evolution of Freudian thought, showing that nothing was set in stone and that few of his ideas were exempt from revision. Were Freud alive today, his theories would have continued to develop. The book also dispels the myth of Freud's complete fixation upon sex as the driving force behind all human activity. Wollheim's style is formal and needs a certain amount of concentration, but if you are a studying to be a psychotherapist, you will find this book a rewarding and insightful read.