This book is one of the most infamous and most cited reference works on werewolves, as it provides an overview of all aspects of lycanthropy: a straightforward scientific review of the literature on shapeshifting. It then discusses the practices of indigenous peoples and continues the topic with case studies of real crimes and criminals, grave robbers, cannibals, and blood fetishists, all of whom are ultimately connected by a thin thread to lycanthropy. It covers various topics, including: lycanthropy in antiquity, the werewolf among the Nordic peoples, the origins of the Scandinavian werewolf, the werewolf in the Middle Ages, a chamber of horrors, Jean Grenier, the werewolf in folklore, natural causes of lycanthropy, the mythological origins of werewolf belief, and Marshal De Retz.