In this paper, the diverse literature bearing on the topic of homosexuality and psychological adjustment is critically reviewed and synthesized. The first chapter discusses the most crucial methodological issue in this area, the problem of sampling. The kinds of samples used to date are critically examined, and some suggestions for improved sampling are offered. The literature is then reviewed under the rubric of four somewhat arbitrary models. The second chapter reviews the cross-species, cross-cultural, demographic, biochemical, and roughly "biological" literature, under the term taxonomic model. The third chapter, on the psychoanalytic model, examines the theoretical and empirical contributions of psychoanalytic thought on psychological adjustment and homosexuality including a detailed critical analysis of the I. Beiber et al. study. The fourth and longest chapter, on the psychometric model, reviews the psychological test literature in considerable detail. The fifth chapter, on the sociological model, reviews the theoretical concepts, empirical data, and ethnographic research that a roughly "sociological" frame of reference has contributed. Each chapter on one of the models contains its own summary. A final chapter attempts to synthesize some of the literature across all the models and discusses a few of the important theoretical issues that arose in the course of this review. (Author)