In this introductory chapter, three facets of professional service and education for it will be discussed. First, an attempt will be made to give some idea of the dimensions of professional service- that is, how many persons at work may be said to be rendering a professional service. The quantitative dimensions of professional work should give some indication of the dimensions of professional education. The second section of this chapter deals more explicitly with the amount of professional education carried on in the United States, the character of the institutions which provide this type of education, and an approximation of the proportion of higher education which is education for the professions. Finally, a more explicit introduction to the remainder of this yearbook is presented by naming and briefly developing fifteen continuing as well as current problems of professional education-problems which all areas of education for the professions seem to share more or less in common.

Undoubtedly the most powerful forces molding professional education are those of history and tradition. A summary of this history has been presented by Brubacher in chapter ii. If one were not to use the dignified words "history" and "tradition," he might use the words "past practices." One may well inquire why many things are as they are. Why, for example, is engineering education basically undergraduate while education for social work, at least the recognized variety, is graduate? Or, why does the basic study for law culminate with a baccalaureate degree, social work with a master's degree, and dentistry with a doctorate? There are, of course, historical justifications for past practices which continue as present practices. But many such practices are often only the result of inertia.

The co-optation of the professional schools by the university, it was pointed out in chapter i, has almost been completed. In addition to incorporating independent professional institutions, the university has spawned a large number of specialized schools and colleges for education in what might be called the junior professions. Thus, schools of education, business administration, social work, criminology, and still others are striving for status and greater autonomy in the modem university.

It has been almost fifty years since the field of educational psychology, with learning as a significant area of study, had its beginnings. The field came of age a little more than a quarter of a century ago with the widespread investigations of learning in such subjects as reading and arithmetic and with general recognition of the necessity for basic training in educational psychology as part of the preparation of the teacher. But in the twenty-five years since the mid-1920's, certain trends in our conceptions of the nature of learning have occurred which today make the field much different from what it was when many who are now teaching first studied it.

Schools should be learning laboratories. This would seem to be the central generalization to be derived from the earlier chapters of this yearbook. Classrooms, which have been the chief centers of instruction, should cease to be lesson-hearing rooms. Rather, they should be centers where children engage in the activities that will lead to the learning which is socially desirable.