On September 28, 1936, at age 9 years 5 months, a Stanford-Binet test given L by Donald MacMurray, a graduate student, showed him to have a Mental Age of between 17-10 and 18-4, and an IQ of from 189 to 195. On January 18, 1939, a Revised Stanford-Binet (1937 form) given L by another graduate student showed him to have a Mental Age of 19-6, his Chronological Age then being 10-8. The IQ thus determined was 183. More dependable is a similar measure made May 5, 1937, by an expert in the Guidance Laboratory at Teachers College (Rosalind Blum). At Chronological Age 10-0, with the Revised Stanford-Binet (1937 Form 1) L's score was Mental Age 19-11, IQ 199. Certain details in the report of this test are worth reproduction here. GUIDANCE LABORATORY REPORT OF L Date of birth: May 6, 1927 CA 10-0 Date of test: May 5, 1937 MA 19-11 Test: Revised Binet, Form L IQ 199 L earned a basal age at Superior Adult I Level. At Superior Adult II Level he successfully completed all the items except interpretation of one of the proverbs. At Superior Adult III Level one more test was passed--Orientation. L was friendly and coöperative throughout the test. Although he had never seen the examiner before, he made an excellent adjustment to the testing situation. Throughout the test he indicated a genuine desire to be as accurate as possible. All his responses were given in great detail and he always told much more than was necessary in order to earn credit. Psychometrically L ranks in the top tenth of one per cent of the population. His intellectual development is very superior. His level of comprehension, vocabulary, memory, and verbal ability are outstanding. He displayed excellent insight into his work and spontaneously criticized his own performance. When difficult items were presented, he frankly admitted that he could not respond accurately. He was persistent in his efforts and devoted excellent attention at all times. He has a good understanding of the limits of his ability. . . . It is impossible to recommend appropriate school placement for this boy, since such ability as he possesses appears in about one out of every million individuals. . . . His emotional, educational, and social adjustments will always be difficult because of his advanced intellectual development. . . . L has acquired a wealth of information. We can be sure of one thing--no matter where this boy attends school, no matter what the teaching devices are, he will always learn new facts and instruct himself. Such intellectual curiosity as this boy possesses will always be satisfied because of his own drive to acquire both information and skills.