Though artists like Coleridge or James Joyce have traditionally been allowed and even expected to have a vivid fantasy life, daydreaming in the average person has generally been held in disrepute by clinical psychologists as an illicit way of indulging in unattainable desires, basically regressive, childish behavior when not actually a symptom of neurotic disturbance. Singer, a Yale psychologist who has been working for years combining introspective, clinical and experimental studies of ""man the image-maker,"" proposes some quite different and much more positive functions for our wide-awake reveries. He suggests that the Freudian ""cathartic"" view of daydreaming is far too restricted to encompass an inborn human talent which ""like our capacity for language or our capacity to develop various motor skills"" is part of our fundamental behavioral repertoire. Singer contends that daydreams range beyond conflict resolution of sexual and/or aggressive drives. Besides providing spontaneous enjoyment and relief from monotony or frustration, fantasies also serve as ""rehearsals for future action,"" a unique and important way by which ""we can explore a great range of future possibilities without necessarily committing ourselves through action to irrevocable consequences."" The old psychoanalytic view which saw daydreams as the opposite of reality no longer seems tenable; considerable evidence is accruing to suggest that a vivid fantasy life may actually help validate a child's sense of ""the real world."" Following Piaget rather than Freud, Singer develops a ""positive-cognitive"" model of daydreaming which suggests that the human capacity for imagery plays a key role in learning and adaptive behavior; pictures which can freely be called to mind again and again are often used to make new information gradually assimilable--viz. the make-believe games of children playing doctor or aviator. A fascinating though still preliminary study. Singer devotes the first chapters to recreating his own very complex and delightful childhood heroic-achievement fantasies.