Although psychologists have related, scientifically and professionally, to the law for over 50 years now, the two fields have not been systematically integrated. Happily, that situation is changing today. Psychologists and lawyers are becoming increasingly aware that laws are based upon assumptions about human behavior, "assumptions about how people act and how their actions can be controlled" (Special Commission on the Social Sciences of the National Science Board, Knowledge into Action: Improving the Nation''s Use of the Social Sciences. Washington, D.C.: National Science Foundation, 1969, p. 35), and that both fields must be concerned with carefully investigating these assumptions and communicating the findings to the legal community, in particular, and to society, in general. This joining of efforts will ensure that our legal system is not only more effective but also more just. Perspectives in Law and Psychology is a regular series of volumes dedicated to this goal. The work presented in this first volume was supported in part by the National Institute of Mental Health, Center for Studies of Crime and De.1inquency, through their grant (MH 13814) to the Law-Psychology Graduate Training Program at the University of Nebraska-Lincoln. Funds from that grant were used to invite six of the contributors to this volume to participate in the first Law-Psychology Research Conference (Michael Goldstein, John Monahan, Norval Morris, R.