A science writer and a doctor have summarized present day findings on that phenomenon which eludes individuals but which now, researched all over the world and in some two dozen laboratories here, seems to be within somewhat closer reach of the investigator. In these clinical bedrooms, electrodes can now record a great deal of material, relevant to both medicine and psychology, on the levels of sleep, the body changes during sleep, the eye movements which reflect the various brain waves, etc. What has been most clearly determined is that sleep loss can be a very dangerous privation; that drugs and alcohol impede the normal patterns of sleep; that hormones can induce a certain relaxation and good deal about the content of dreams can be assessed. Some (if not a good part) of the material here will have parallel coverage in David Foulkes The Psychology of Sleep which will appear on the Scribner list next month and to whose work the authors here refer. They also indicate a good many of the rituals and idiosyncrasies connected with sleeping but for the insomniac, there's not an encouraging word until further drug research is completed. He will just have to count sheep or stay awake... a very good bibliography indicates the exhaustiveness of the research which does not impede the capable, popular presentation here.