We've got no more time for perversity - let's hear it for diversity

Jeffrey Weeks' Sexuality was first published in 1986. This second edition amply justifies the blurb's promise to discuss sexuality's "cultural and socio-historic construction, its relationship with power and the state's involvement in its rationalisation and regulation" as well as more contemporary topics such as Aids.

The signs of his excellence as a communicator are everywhere.

Without sacrificing complexity of argument, he minimises his notes and sets out in orderly numbered lists the evidence on which he identifies areas crucial to sexuality's social organisation.

Weeks is cautious about taking up positions that might compromise his claimed "radical pluralism", but he nevertheless risks stepping out from behind his erudition to "lay himself on the line".

The book ranges widely. The basics are established in its conclusion on the nature-culture debate in favour of an emphasis on society and social relations rather than on nature. Weeks' brushes with science and especially genetics - he shows justifiable scorn for the results of the so-called "gay gene" discovery - are particularly stimulating, but he also tackles anthropology (especially Margaret Mead), sociology (the danger of confronting biological with sociological essentialism) and psychoanalysis (with its recognition that sexuality is a problematic category). From Michel Foucault he takes sexuality as a relationship of elements and discourses, from Alfred Kinsey awareness of hitherto unsuspected sexual diversity.

Weeks clearly espouses relativism and prefers "sexualities" to the singular in his title, arguing bravely at one point for "paedophilias" in the plural, and for "diversity" over "perversity". Aware of the potential moral vacuum in categorising sexuality as a social convention, he advocates not only a break with a moral system based on acts but the weighing of the impact of a sexual activity on oneself and others. The radical pluralist approach, while tentative and open-ended, aims "to provide guidelines for decision-making rather than new absolute values".

The book's achievement is partly to show how vast its subject is. The second edition remains compact and leaves some questions unanswered, for example, if sexuality always involves interaction with others, does that necessarily preclude consideration of "cybersex" as part of sexuality? But students should be grateful for the many questions that are answered.

Kenneth MacKinnon is professor and principal lecturer in film studies, London Metropolitan University.