The principal task of this book was to examine some of the research evidence concerning the relation between personality and school achievement. Its source was the empirical research which bears on this issue rather than the various theories of personality. The reason for this was that the implications of many theories of personality for educational practice are obscure; the apparent plausibility of most theories is not sufficient reason to force educational practices into their framework. The concern was to take those aspects of education and personality which have been subjected to measurement, to see if consistent, orderly and systematic relations are present between personality characteristics and attainment. This has meant that nearly all the studies which have been considered are implicitly or explicitly correlational in design. To that extent they are descriptive studies. Our review showed that the situations to be explained are multiple and complex. The notion of underachievement provides a point of departure for studying the effects of personality characteristics on achievement by calling attention to the fact that individual differences in performance are not totally explained by individual differences in intelligence. It can easily be forgotten, however, that these notions are relative to the prediction of performance from intelligence, which is not and cannot be perfect. To regard such achievers as educational "problems" is to ignore the possibility that other variables may systematically affect performance. (Author/JM)