Up to a very few years ago even psychologists and psychiatrists considered the mind of primitive man to be that of civilized man but untutored, the mind of the child to be that of the adult but weak and undeveloped, the mind of the psychotic to be that of the normal but with certain parts (perception or intellection) not clicking properly. Gradually in the last fifty years (with increasing rapidity in the last twenty-five) has come the realization that the minds of the primitive, the child and the psychotic differ from ours structurally and that all of them show certain structural similarities. Even today however the nature of these similarities or parallels are not completely understood, and even psychologists often fall into the error of directly equating primitive mental mechanisms to the mental mechanisms of the child or of taking literally the description of psychosis as 'a regression to childhood'.

Werner's book brings order into this field and that is perhaps the chief of its many virtues. After a meticulous and exhaustive