A complete survey of a broad field of science dating back to the dawn of history is rarely attempted in the day, but the present work is an example of such a study. The scope of this work is truly comprehensive, and an effort has been made to include references to all published work which has appeared since antiquity. Persons carrying out research on these animals and their toxins know well the difficulties of surveying the literature, difficulties due in part to the appearance of much important information in sources other than research publications. There are a host of poisonous and venomous animals known to be capable of inflicting severe injuries in man, and yet chemical and pharmacological studies are nonexistent. Possible roles of most of these toxins in the ecology of the animals have not been investigated in spite of the obvious importance of this aspect. This is a definitive work in an important but neglected area of biology, and this treatise will be a major reference source for decades.