Rickettsial diseases, which include typhus, spotted fever, trench fever and Q fever, are very serious infectious diseases. Rickettsiae organisms also are of interest to researchers because they have been used as bioweapons, and can serve as agents for bioterrorism. In addition, they are biologically very successful organisms despite their relatively small genome. The papers in this volume are taken from the International Conference on Rickettsiae and Rickettsial Diseases, held in Ljubljana in 2002. They include state-of-the-art discussions of functional genomics, proteomics, epidemiology, ecology and clinical and diagnostic medicine.