This is the tenth year in which the literature on abnormalities of be havior has been surveyed in the Annual Review of Psychology. A back ward glance over the decade shows that there have been certain significant changes of interest. The shadows of war still lay over the earlier volumes, which gave considerable attention to war stress and to such war-born investigations as the Minnesota semistarvation project. Even more popular at that time were the lobotomies and the convulsive therapies, reports of which were occupying large amounts of space in psychiatric journals. Last year, in contrast, there were relatively few papers on these forms of treat ment. Those on lobotomy and on insulin shock had decidedly the air of a mopping-up task, whereas those on electroconvulsive therapy might be de scribed as sedately mature and judicious. But youthful vigor and unguarded optimism are still abundantly present: one finds them now in the flood of articles on the wonderful effects of the ataractic drugs. Some of us who accommodated ourselves with difficulty to the idea of treating behavior dis orders by violence are much gratified that the fashion has swung toward treating them by chemically induced tranquility. Yet it is disquieting to find in sober science such rapid changes of enthusiasm as have characterized recent work on the physical side of mental disorders.To understand any topic of research it is helpful to consider where it stands in what may be called the cycle of discovery. The first stage, which we may call birth, is ushered in by some kind of break-through, some momentous discovery of fact or technique which opens a whole new range of possibilities. Then follows a period of childhood, buoyant in spirit, during which the discovery is exploited and extended. Reported results are mainly positive, a simple systematic explanation seems to be forming, and therapeutic effects, if they are involved, are said to be astonishingly good. N ext comes the third or adolescent period, filled with doubt and criticism; reported results are apt to be inconclusive or negative, rival theories be come prominent, and therapeutic effects are dubiously satisfactory. The fourth stage is one of maturity, marked by the appearance of sophisticated discussions in which the limits of the original discovery are recognized and its precise consequences worked out in detail. Then comes senescence, when research settles into a plodding routine or concerns itself with minute and rather precious details, and when theory becomes conservative and orthodox. The urge toward discovery is so insistent that we rarely witness a final stage comparable to death, though the spectacle of a research area in bad 1