Studies on the role of infection and inflammation in sudden infant death syndrome (SIDS) have been published over the years in a variety of journals dealing with pathology, infectious disease, paediatrics, genetics and epidemiology. In 1999, FEMS Immunology and Medical Microbiology published a special issue of up-to-date reviews and papers from groups working on different aspects of infection in SIDS. This was found to be a very useful reference, and it was suggested that it was time for an update. There have been significant advances in this area in the last five years, particularly in addressing the mechanisms underlying the risk factors for SIDS, such as exposure of infants to cigarette smoke and increased risk of SIDS for infants sleeping on cot mattresses previously used by another family. The collection is divided into three themes: infection; inflammatory and immune responses; genetics. For each theme there are both MiniReviews and Research articles. In the section on infection, two MiniReviews (Vege, Goldwater) examine the pathology-based data that indicate infections are involved in the majority of these sudden deaths in infants. Goldwater's critical analysis of pathology findings in relation …