The maternal great-grandfather was a famous rabbi who compiled and published a Jewish calendar covering a period of 414 years. This calendar contains, in regular order, the exact period of every new moon's appearance, the sabbaths, festivals with scriptural portions for each, and the equinoxes of the solar year according to the prescribed and authorized Jewish laws and corresponding to dates in the common era. The tabulations have been carefully compiled from various works of ancient rabbinical astronomers, with annotations in Hebrew and English. This rabbi was also the great-grandfother of the four first cousins of D, whose intelligence quotients have been taken, and who rated 156, 150, 130, and 122, respectively. A second cousin in the maternal line yielded at the age of 6 years an IQ of 157. PRESCHOOL HISTORY D cut his first tooth at 4 months of age. He could say words at 8 months and talked in sentences at 11 months. In November, 1910 (8 months), he said "little boy" when his shadow appeared on the wall. D could stand, holding to chairs, at 9 months of age, and he walked alone at 11 to 12 months. At the age of 18 months, while sitting on his mother's lap as she sat before a typewriter, he learned to read by looking at the letters. The records kept by the mother indicate that he "learned to read and count in 1911." One such record reads, "October 11, counts all day long." At 8 months of age D strung in succession 5 yellow and 5 red balls and then began on blue, when the activity was interrupted. In March, 1912, he was using words to express relationships, such as "will" and "shall" (correctly), "but," "and," "my," "mine." At 2 years 6 months his vocabulary (incomplete) was 1690 words. D's earliest memory goes back to 2 years of age, when he saw a rat and thought it was "a little brownie." An example of the quality of the questions asked by D in the first 36 months of life is one he asked in October, 1911 (19 months): "Has every door two knobs?" "Why?" His mother reports: "He was always asking unexpected questions." This child was not placed in school at the usual age because he did not fit into the school organization. At the time he should have entered kindergarten D could read fluently and could perform complicated arithmetical processes. His intellectual interests were far beyond those of even the highly selected children of a private kindergarten. Therefore, his parents kept him out of school and obtained the companionship of other children for him by sending him to a playground. D was first seen by the present writer [[L. S. H.]] while he was attending this playground, in the year 1916-1917. It is very interesting to note how D made social contacts with the other children while pursuing his own interests. For instance, he published a playground newspaper called "The Weekly Post." [2] He composted, edited, and typed this paper, issued at intervals, and it had a regular playground circulation. TRAITS OF CHARACTER