Taking William A. White's thesis of the not quite understandable something which enters into all human relationships, Dr. Loomis has attempted to explain 'the Third Component' by a series of thoroughly enjoyable stories of its occurrence, or the occasional lack of it, in his own medical experience. A few chapters are devoted to the pleasant teaching of those otherwise untutored in the art of knowing doctors and entering, residing in, and leaving hospitals gracefully. Dr. Loomis remarks toward the close of his book, 'Sometimes one may not even know what invisible evil spirit is really troubling him, so deeply buried it may be beneath the obvious and visible results. As Goldstein says in his Human Nature: "Human behavior cannot be understood on the basis of consciousness alone but embraces a great number of events of which we are not conscious."' Though unfortunate, this statement stands almost alone in that category and should hardly deter the expectant reader from a very pleasant encounter with the mind of a man who writes simply, easily, and well.