The study reported here, the fourth of a series of studies on adult education in Organization for Economic Co-operation and Development (OECD) countries, provides quantitative evidence about the magnitude and characteristics of adult education activity in nine OECD countries. The nine countries included are Austria, Canada, Denmark, Germany, Italy, the Netherlands, Sweden, United Kingdom, and United States. An introductory chapter briefly comments on the problems involved in collecting data about participants, participation, and expenditures in adult education. Nine papers then follow with each one devoted to the status of adult education in each of the nine OECD countries. For each country, the papers describe the prevailing frameworks within which adult education is provided, give rough estimates of the percentages of national populations participating in educational programs in any one year, provide some indication of the socioeconomic characteristics of participants, and identify the areas of research most needed regarding expenditure. Finally, a tenth paper proposes some strategies to make comprehensive and up-to-date information about enrollment and program statistics more readily available in the future. (EM)