ACD, as it is called at home, is a common T cell-mediated disease of the skin with a high socioeconomic impact in both professional and nonprofessional settings. More to the point here, it represents one of the most reliable and informative models for understanding dendritic cell and T cell biology, and so has been studied extensively by immunologists. In these 12 studies, European and American immunologists and dermatologists explore not the disease itself so much as what research into its immune mechanisms has revealed about immune response in general. Among their topics are the molecular recognition of haptens by T cells, Langerhans cell migration and the induction phase of skin sensitization, and the multiple roles of keratinocytes in ACD. Annotation : 2004 Book News, Inc., Portland, OR (booknews.com).