The virology section of this 2001 ‘A Year in Review issue covers a large spectrum of HIV research topics. Even if these fields may appear similar to those covered in previous review issues the amount of knowledge that has accumulated recently within each of these domains is truly impressive. Research on HIV entry into target cells still benefits from the momentum provided by the 1995 discovery of the role of the chemokine receptors. Research on HIV assembly has become a more comprehensive field as detailed knowledge on protein structure and protein interactions has emerged. Research on HIV accessory genes has widened and gained in complexity as novel cellular partners have been identified bringing further insight into the complex network of interactions that underlies the regulation of HIV replication in its host cell. In the shadow of the major therapeutic advances of highly active antiretroviral therapy HIV drug resistance has emerged as a field of increasing interest and complexity altogether relevant to clinical management of HIV infection protein structure/function relationships viral genetics and viral pathogenesis. Finally HIV-2 long considered a remote and secondary problem has been the subject of studies that are likely to have a significant impact on multiple domains of HIV research. (excerpt)