Even a man who's pure in heart

And says his prayers at night,

May become a wolf when the wolfbane blooms,

And the moon is full and bright.

The Wolf Man

Speaking of legends, that of the werewolf is one of the most persistent in the history of civilization.

The belief that a man can become a wolf under certain conditions is ancient and very strong. Throughout history the contemporary police have actually attributed many recorded murders to werewolves.

Even today there are, in a few isolated sections of Europe, people who fear the light of the full moon and refuse to venture into the darkness of night. Their reasoning is quite explicit: this is the time when the lost soul walks in the form of a wolf, searching for a human victim.

Surprisingly there does exist a certain disorder of the mind that strongly resembles this strange superstition, and it may have been the cause of the original belief in werewolves. The disease is known as lycanthropy.

Medically speaking, lycanthropy is a form of acute mental illness in which the victim actually believes he is a wolf. While in this demented state he will imitate the physical activities of a wolf on the prowl and can be dangerous. Rare as this disease may be, several cases are being treated by psychiatrists at present!

It can be said, however, with little fear of contradiction, that the only place that a man can be transformed physically from a man to a wolf is in Hollywood.

From the book: 
Our Fascinating Earth