Why do children go to school? Why do they now spend more years in school than in the past? Why does education expand? If we could answer these questions we would know much about the nature of formal education and about the evolving relationship between education and the social order. Yet, until recently scholars rarely even asked such questions. As a subject of serious analysis, the expansion of education enjoyed little of the glamour and popularity of economic development, the population explosion, and other constituent parts of what have been termed societal growth (Hawley, 1979). In the world of research on social change, it was a second-class citizen. This is no longer the case. In recent years scholars in several disciplines have exhibited mounting interest in the causes of educational expansion. They have explored the subject in a variety of settings and have advanced numerous hypotheses relating the growth of schooling to such processes as industrialization, urbanization, and the rise of the modern state. One can no longer complain that the subject is unduly neglected. But there remains cause for concern. Although there are now several excellent studies of educational expansion in specific contexts, the overall impression left by the literature is one of fragmentation and incoherence. As yet there has been little dialogue across disciplinary or ideological frontiers. There also has been little attention paid to comparisons across societies or across historical periods; few students of educational expansion have drawn on evidence from more than one country or from more than one period. This is not to suggest that studies of the sort that now characterize the literature have outlived their usefulness. In the future most research on the causes of educational expansion should and no doubt will involve case studies of specific societies in specific periods. But such research can only profit if it is