1. Purpose This study has two main objectives: The first is to provide some clinical data to justify Dr. Wechsler's idea of general intelligence-the behavior theory-and to prove Dr. Alexander's idea of X and Z factors-the temperamental and personality factors theory. The second objective is to provide my own idea -the life history theory. 2. Method After I finished the Japanese standardization of WISC in 1953, I started clinical case study of children and analyzed more than a thousand cases. 3. Results What I have found is as follows: By measuring children's intelligence with WISC, we not only can find personality factors, but also can diagnose children's life histories-how children are brought up and what their parents' attitudes are like, and so on. I have listed ten illustrative cases showing brief case histories and Verbal I. Q., Performance I. Q., Total I. Q., and Scaled-Score profiles.