It is without question thatthis text is among the mostresourceful and insightful works ever written upon the subject of atavistic violence. Dr. Eisler's book (which actually began as a lecture to the Royal Society of Medicine) contains a very insightful look into the sub-rosa subjects of lycanthropy, sadism and masochism. This text details aspects associated with primal actsof violence and delivers a well formated theory to explain such behaviors. This under addressed book is a must for any student of Psychology seeking the defining factors of violence associated with abnormal psychosis.