This slim little book, based on three lectures delivered at Manchester University in 1952, succeeds in its intention of serving as a real introduction to Piaget's methodology for arriving at his chronological assessments of a child's increasing capacity for conceptualization. He demonstrates his rationale as being an application of the 'algebra of logic'. Piaget expresses himself with that admirable but unequivocal conciseness which so often characterizes those whose aim is to bring orderliness to that which is overt. Within these limitations, as we know, he has discovered and formulated many important data on the cognitive and behavioural responses of babies and children to his excellently devised test situations.

With the aid of this compact, pocket-size book, one is admirably inducted into a quicker understanding of Piaget's guiding principles and terminology than could be achieved in any other way.