This is the report of an experiment. Twenty percent of the children at an unidentified elementary school in a lower-class community were reported to their teachers as potential ""bloomers."" The children had been chosen quite at random, and the teachers were told to expect noticeable spurts in intellectual growth. The difference between the special children and the ordinary children was entirely in the mind of the teacher. But eight months later, these ""magic"" children showed significantly greater gains in IQ than did the others. ""Teachers brought about intellectual competence simply by expecting it."" The authors, a Harvard psychologist and a San Francisco school principal, offer a wealth of anecdotal evidence--presented very readably as well as rather conclusive experimental data. The book is directed at graduate students, educators, and intelligent laymen. The appendix includes quantitative data, but there is a key to statistical symbols. There is nothing radically new here except for the on-location documentation. The notion of ""self-fulfilling prophecy""--that professionals can effect change simply by expecting it has never been so carefully tested in the classroom. The authors consider the possibility that the change also might be only in the mind of the teachers. But pupil performance was tested on objective tests. The prognosis; changes in teacher training. For if a teacher possesses the power of Pygmalion, he must learn to direct it.