'John Carroll has done a magnificent hing: He has reviewed and reanalyzed the world's literature on individual differences in cognitive abilities, collected over most of a century, to reach an integrated picture. No one else could have done it. No one else would have applied so consistent and impartial a system on the literature, an dreached so balanced, complete, and ... Read moreuseful a conclusion. It is a monumental contribution, destined to be brought and read in every university the world over that has a psychology or education department, and to be on many an individual scholar's shelf as well. It defines the taxonomy of cognitive differential psychology for many years to come.' Richard E. Snow, Stanford University Show Less