Preface: the evolution of parasite genomes and the origins of parasitism

From a human perspective it seems intuitive to view life as essentially free-living, and parasites as specia-lized derivatives. Certainly, this is the impression given by biology teaching or the balance of research effort. In fact, it is just conceivable that parasites are more numerous than non-parasites (Dobson et al. 2008), and while this may be difficult to prove, they are clearly abundant and ubiquitous throughout evolutionary history (Conway Morris, 1981). Today, we appreciate the great importance parasites have for the ecology, behaviour and evolution of free-living organisms, but also for biodiversity and ecosystem function (Lafferty et al. 2006; Kuris et al. 2008; Dunne et al. 2013). As moderators of trophic dy-namics and competition between free-living species