The preschool history of A has been elicited from the parents and from the "baby book" kept by them. A was born at full term, and the birth was normal in all respects. He weighed 7 pounds 9 ounces, and was breast fed for the first several months of life. He began to articulate words at 10 months, and at 14 months could pick out letters on the typewriter at command. At 12 months he could say the alphabet forward, and at 16 months he could say it backward as well. His parents had no idea that he could reverse the alphabet until one day he announced that he was "tired of saying the letters forward" and guessed he would "say them backward." The concepts of "forward" and "backward" had thus been developed by the age of 16 months. At 12 months he began spontaneously to classify his blocks according to the shape of the letters on them, putting V A M W N together, Q P O G D together, and so forth. This love of classifying has remained one of his outstanding characteristics. As an infant, he would for hours thus amuse himself with his alphabet blocks. When 18 months old he was able to carry out simple errands involving not more than three or four items. By the time A was 30 months old he could copy all the colored designs possible with his kindergarten blocks. Before the age of 3 years he enjoyed rhymes, and would amuse himself rhyming words together. From the time he was old enough to be taken out to walk, he would point out letters on billboards and signs with keen interest and delight, crying, "Oh, see D! There's J, Mother! There's K and O!" Also before the age of 3 years A objected to stories containing gross absurdities. For instance, he rejected the story of the gingham dog and the calico cat who "ate each other up." A pointed out that this could not be, "because one of their mouths would have to get eaten up before the other mouth, and no mouth would be left to eat _that_ mouth up." He was irritated by this obvious lapse from logic and requested that the story be read to him no more. A learned to read for himself during the third year of life, and read fluently before he entered school. The photograph in Figure 1 [not included] shows one of A's amusements at the age of 10 months--balancing and rolling simultaneously a large ball between his hands and another between his feet as he lay on his back in his crib. This activity illustrates his power of motor coördination in infancy, and it is especially interesting in connection with the errors of judgment made by A's teachers to the effect that "A is below average in control of his body." FIG. 1. CHILD A AT THE AGE OF 10 MONTHS. SCHOOL HISTORY