Abstract
There are many ways of approaching research on AIDS, and sometimes different philosophies clash. Robin Weiss (Chester Beatty Laboratories, Institute of Cancer Research, UK) wryly portrays the differences between the experimentalists and the theorists as they try to understand how the interactions of HIV and its human host result in disease. He also presents his view that recent discoveries of cofactors for HIV entry highlight the improtance of a cell biology—centered approach to understanding pathogenesis.