The rapid development and the increased competition in the labor market make continuing education a necessity for an increasing number of people. Equal opportunities for adults to engage in education are therefore important in order to combat exclusion from the labor market. To increase the provision of equality in opportunity for engagement in education we need to understand the psychological processes involved in participation in education. This report presents results from a European Commission Leonardo da Vinci-supported study of adult education in Great Britain, Norway, and Spain. The purpose of the project was, in a comparative perspective, to analyze psychological processes involved in participation and non-participation in adult education. The study focuses on the scale of participation, both in general and in different types of courses: which groups of adults participate the most, motivational aspects of participation, barriers to learning, conceptions of learning, and perceived benefits of adult education.