Some years ago, the writer completed a thesis, in the course of which an attempt was made to clarify some of the psychological problems involved in the concept of “work", and to relate these to educational techniques . This led to a consideration of the relationship between "output" and "method", and an appraisal of some of the outstanding studies in industrial psychology in so far as they were relevant to educational problems of the same general type. One of the problems centred around the study of work methods - e.g. study habits and skills, and some of the implications of these methods of improving performance, for example the relation of performance to capacity in intellectual tasks. Since that time, the problem has undergone several stages of transformation and has finally materialised in the form of this thesis. A brief account of these transformations will put the present thesis topic in perspective, and account for the particular way in which it has been handled.