This volume--the second in a two-volume set from the Monitoring the Future study--provides findings on the substance use and related behaviors of several segments of the adult population. It also contains findings on attitudes and beliefs about drugs, as well as on several particularly salient dimensions of their social environments. Volume I presents similar findings for American secondary school students in grades 8, 10, and 12. One important segment covered here is the population of American college students; a second is their age peers who are not attending college. Also covered in this volume are young adult high school graduates ages 19 to 30 (including the college students), as well as high school graduates at ages 35, 40, and 45. Monitoring the Future is a long-term 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. Now in its 31st year, it comprises, in part, ongoing series of annual nationally representative surveys of 12th-grade students (begun in 1975) and of 8th- and 10th-grade students (begun in 1991). (Contains 40 tables and 58 figures.) [For Volume I, see ED494056.]