This edited volume on the nematode model Pristionchus pacificus describes an integrative approach to evolutionary biology. It aims for a merger of evolutionary and comparative biology with mechanistic approaches based on genetics and molecular biology. Insight into the function of biological systems obtained from laboratory studies when complemented with ecology, natural variation and natural history of an organism, can provide detailed knowledge of the proximate and ultimate causations of species. Ralf J. Sommer developed P. pacificus as model system for integrative...