Monitoring the Future (MTF), now in its 40th year, is a research program conducted at the University of Michigan's Institute for Social Research under a series of investigator-initiated research grants from the National Institute on Drug Abuse--one of the National Institutes of Health. The study comprises several ongoing series of annual surveys of nationally representative samples of 8th- and 10th-grade students (begun in 1991), 12th-grade students (begun in 1975), and high school graduates into adulthood (begun in 1976). The current monograph reports the results of the repeated cross-sectional surveys of high school graduates since 1976 as we follow them into their adult years. Segments of the general adult population represented in these follow-up surveys include: (1) American college students; (2) Their age-peers who are not attending college, sometimes called the "forgotten half"' (3) All young adult high school graduates of modal ages 19 to 30 (or 19-28 for trend estimates), which are referred to as the "young adult" sample; and (4) High school graduates at the specific later modal ages of 35, 40, 45, 50, and 55. In this volume, historical and developmental changes in substance abuse and related attitudes and beliefs occurring at these age strata receive particular emphasis. The follow-up surveys have been conducted by mail on representative sub samples of the previous participants from each high school senior class. This volume presents data from the 1977 through 2014 follow-up surveys of the graduating high school classes of 1976 through 2013, as these respondents have progressed into adulthood. The oldest MTF respondents, from the class of 1977, were the first to be surveyed through age 55 in 2013. Other monographs in this series include the "Overview of Key Findings, which presents earlyresults from the secondary school surveys; Volume I, which provides an in-depth look at the secondary school survey results; and the HIV/AIDS monograph, drawn from the follow-up surveys of 21- to 40-year-olds, which focuses on risk and protective behaviors among young adults related to the transmission of HIV/AIDS. To enable the present volume to stand alone, much of Chapters 2 and 3 from Volume I have been repeated. Chapter 2 provides a summary of key findings from five of the populations under study (8th graders, 10th graders, 12th graders, college students, and young adults). Chapter 3 outlines the study design and procedures. [For "Monitoring the Future National Survey Results on Drug Use, 1975-2014. Volume 1, Secondary School Students," see ED578369.]