For the past two generations, extensive research has been conducted on the determinants of homosexuality. But, until now, scant attention has been paid to what is perhaps the most mysterious--and potentially illuminating--variation of human sexual expression, bisexuality. Today, as ignorance and fear of AIDS make greater awareness of all forms of sexual behaviour an urgent matter of private and public consequence, leading sex researchers Martin Weinberg, Colin Williams, and Douglas Pryor provide us with the first major study of bisexuality. Weinberg, Williams, and Pryor explore the riddle of dual attraction in their study of 800 bisexuals, homosexuals, and heterosexuals living in the San Francisco Bay area. Fieldwork, intensive interviews, and surveys provided a wealth of data about the nature of bisexual attraction, the steps that lead people to become bisexual, and how sexual preference can change over time. They found that bisexual men and women differ markedly in their sexual behaviour and romantic feelings; that most bisexuals maintain long-term relationships which continuing sexual activity outside those relationships; and why trans-sexuals often become bisexual. Further, this is the first study to compare directly large samples of bisexuals, homosexuals, and heterosexuals. Among the differences: bisexuals were the most fluid in their sexuality--changing most over time--and in the composition of their feelings, attractions, and behaviours. The authors also found some interesting similarities between the groups: for example, bisexuals and homosexuals showed the same degree of confusion in the development of their sexual preference and for similar reasons; also heterosexuals were not immune from such confusion. Bisexuals, heterosexuals, and homosexuals all reported same-sex erotic desires, but to different degrees. Finally, the authors studied the social and sexual effects of AIDS. For example, they discovered that as the AIDS crisis unfolded, many bisexual men entered into monogamous relationships with women, and bisexual women into more lesbian relationships. Recent media accounts attest that a growing number of researchers and writers are narrowing the fundamental cause of sexual preference to a single factor: biology. But if, as this study shows, learning plays a significant part in helping people traverse the boundaries of gender, if past and present intimate relationships influence their changing preferences, and if bisexual activity is inseparable from a social environment which provides distinctive sexual opportunities, then a mosaic of factors far more complex than those previously considered must be entertained in explaining the fuller spectrum of sexual preference. Dual Attraction is one of the most significant contributions to our understanding of sexuality since the original Kinsey reports and Bell and Weinberg's 1978 international bestseller Homosexualities. It is must reading for all those interested in the study of sexual behaviour--especially now, since the onset of AIDS.