Parasites and infectious diseases are everywhere around us and have affected the ecology and evolution of organisms since the early days of life on this planet. In fact, this second edition of Evolutionary Parasitology was finished during the Corona year, 2020. The pandemic brought grief and misery to many people, not to speak of the enormous economic costs. At the same time, this pandemic is an impressive illustration of the pervasive influence of parasitism that affects virtually all aspects of the hosts’ lives. The field of evolutionary parasitology, therefore, cuts across many disciplines for a more comprehensive approach to studying hosts and parasites, to appreciate the mechanisms that guide their interactions and to identify the selective forces that shape their biology.