Matt Kaplan's study asks why human beings feel compelled to create monsters.
He uses science to explain myths and legends: fire-breathing dragons may have been invented to account for dinosaur bones; vampires probably originated in fears about infectious diseases such as rabies. But Kaplan doesn't simply debunk, and intriguingly lends credence to some apparently fantastic stories. There may well be some truth in the tale of Hercules battling a giant lion: it's possible that the remnants of a now-extinct Eurasian species prowled Ancient Greece.
The book occasionally gives the impression of being hastily written: Kaplan tells us that "no fuzzy or remotely mammal-like dragons have ever been described", before going on to list the mammalian characteristics of Chinese dragons. But this is for the most part a fascinating read.