There are many topics in modern psychology about which speculation has been rife for hundreds of years. Much has been written (and some of it amusing) on the powers and dangers of the hypnotic trance, the wonders of telepathy and clairvoyance, the possibility of the interpretation of dreams, the nature and assessment of personality and the psychology of beauty. In recent years, however, much experimental evidence has been collected regarding all these topics and the author has attempted to give a reliable account of it in this book, frankly acknowledging ignorance when the facts are still in dispute and boldly putting forward a definite point of view where the evidence appears to justify it. Throughout the book emphasis is laid particularly on the detailed discussion of the facts, leaving to the reader the decision as to whether the conclusions drawn are justified.