From the Arcadia to which Theocritus and Virgil sang to the frozen North of the Icelandic sagas, from the Ireland of the saints to the gloom of the Baltic forests through the Ukraine of Prince Vseslav of Polock, the intolerant Switzerland of Calvin, the violent Luther's Germany, the France of religious struggles, Spain and Portugal; In short, from one end of the western world to the other, and long before that Antiquity that we named Classical, there have always been werewolves. They survived the systematic extermination to which, in many European countries, the wolves and also the multiple fires of the Inquisition were subjected. They have been seen loitering even in those latitudes where the wolf has never existed. They are a monstrous idea, they are the fruit of imagination, of fear, of night and ignorance. Its reality is based on an enormous variety of curious ideas -and, on more than one occasion, absolutely crazy-, that the West has accumulated, over more than two thousand five hundred years, in hundreds of stories that, with justice, They deserve to be described as wonderful. The many pages that generated through that lapse are the subject of this book, which brings together myths, legends and philosophical, religious, literary, scientific, anthropological, legal and journalistic texts, compiled over a long time.