As definite as this question is and as easy of solution as it may seem, it is only very recently that reliable data, as distinguished from unsupported opinions, have begun to be accumulated. The problem is complicated by the difficulty of securing satisfactory measures of success in later life, and by the difficulties encountered in following up the careers of those individuals whose early records are known. Shall success be measured by the obstacles overcome, the income earned, the sacrifices made, the social usefulness accomplished, the amount of local and contemporary publicity received, the public recognition accorded, the scope of activities attempted, or the historical eminence merited? And if more than one of these elements are to be considered, how are they to be treated commensurately? Certainly success may be achieved in any or several or all of these and other forms. For the present our information is limited to a few studies in which one or other of these aspects has been treated separately. As work in this field progresses we may be better able to sum up all the partial results into a statement of the general tendencies. For our present purpose it may be best to bring together from various sources the data bearing on certain specific questions which have been propounded. At least three of these questions are distinctly relevant to the work of vocational psychology. _I. With respect to school work itself, what relation exists between the early success in elementary subjects and the later success in handling more advanced subject matter?_ This question is important to all those who may be concerned in advising individuals concerning the desirability and probable profit of continuing their school experience, and of entering occupations in which scholastic abilities may be requisite. Kelley has recently reported a careful study of the relation between the marks in the fourth, fifth, sixth and seventh grades and the marks received in the first year of high school work. The results, in the case of fifty-nine pupils followed through the six years, were as follows: CORRELATION BETWEEN MARKS IN THE GRADES AND MARKS IN FIRST HIGH SCHOOL YEAR 7th grade .72 6th grade .73 5th grade .53 4th grade .62