Estimates of the annual value of volunteer services in the United States for the period from 1965 to 1974 are presented in this study, with the first goal being to estimate the value of volunteer services for the benchmark year 1974. Its reference points are based upon the results of a national survey of volunteer services sponsored by ACTION (agency for volunteer service) in 1974, and the Department of Labor's 1965 study, "Americans Volunteer." The period from 1965 to 1974 is also analyzed, with alternative assumptions concerning the scope of volunteer services. Secondly, this study analyzes the problem of constructing these estimates, as well as certain methodological and substantive issues raised by the study. Third, it introduces the concept of unorganized volunteer services and explores such issues as their contribution to total volunteer product and the possibility of understatement since this fact was omitted in the Labor and ACTION surveys. Finally, after a discussion of the institutional root of volunteerism, the study concludes with recommendations for further surveys and research. (WL)