The house mouse, Mus musculus, is undoubtedly one of the best experimental animals for biomedical research. Because of the similarity between the genetic organization of mice and humans, the mouse is an indispensable tool for genetic approaches to human diseases. However, as classical laboratory strains are highly inbred, polymorphic markers for mapping disease-associated genes are not always available. Wild mice can provide this variation, and can also be used for seeking novel phenotypes for use in biomedical research. Taken together, the contributions to this volume provide an up-to-date review of current knowledge of the genetic profiles of a large variety of wild mice and wild-derived strains.