This volume contains a section on the wider evolutionary context of venom in animals, the molecular evolutionary processes involved in generating diversity, and the concept of venom evolution as being driven by an arms race that also involves evolution of resistance to toxins by prey. It also studies the relationship between the evolution of toxins and the evolution of the animals that they evolved within. The last section discusses the evolution of venom delivery systems. The definition of a venomous animal, as opposed to a poisonous one, encompasses the evolution not just of toxins but also a specialized mechanism for administering them by injection. .