The author encounters a village where no one will guide him to the city because they are afraid to venture out while it is night. They think they will be attacked by a werewolf they claim is roaming the area. Curious about their claim, he begins to explore the lore of werewolves. He learns where some of these stories might have originated, and why people still believe they exist. Exploring myths, folktales, trials, and stories of brutality we enter the world of the werewolf. The main theory presented is the need to explain many of the brutal murders, often of serial killers, that people encountered. The brutality of a monster is used to explain the horror of these deaths.
Many of the tales used to illustrate the author's point were from Icelandic Sagas. The Beserker often wore animal skins and had an animal like rage and strength come over him, that he couldn't control. They would usually be exhausted after such a spell. The description of these spells matched the details some of the violent killers(thought to be werewolves) gave during their trials.
In medieval times, people were hung when accused and found guilty of being a werewolf. This was usually accompanied with a charge of witchcraft because the accused would claim to consort with the devil for the power to change form. Cannibals were also charged with being werewolves because of the violent crimes they committed to eat people. Often these people thought they changed form into a wolf.
I thought this was an interesting examination of the werewolf myth, and why it was believed people could change form. One of the biggest issues I had with the book, was that there are many passages to make the author's point, usually in Greek or Latin, that aren't translated. This is an unfortunate result of those two languages being considered essential for an educated person in the 19th century, and that no longer being true. It was an excellent source for a collection of early tales and theories on the werewolf, and how they were connected to the very violent people in society. I would recommend this book if you are interested in a serious perspective on the werewolf myth.