Written in 1936, this book seeks to describe what is required of an investigator into the unconscious mental processes of another person, and what he achieves. By describing the psychological process of cognition from within, the author intends at the same time to trace the way from conjecturing to comprehending the unconscious processes.-Print ed. "The author describes his book as an attempt to set forth "What is required of an investigator into the unconscious mental processes of another person, and what he achieves." In fact the scope of the book is wider than this might suggest, for it makes a good many incursions into the fields of general psychological method and principle both normal and abnormal. Some of the topics dealt with are wit; tact, time and rhythm; memory and reminiscence; conjecture and comprehension; the ego mechanism; anticipation. The general thesis of the book is that when the true route of analysis and interpretation is followed there must be somewhere near the beginning always an experience of shock or surprise. This and its significance are fully discussed and illustrated by a mass of original observations."-American Psychological Association.