From publisher blurb:
Harpies are cruel and vicious monsters that delight in the suffering of others. They also elevate selfishness and narcissism to new heights in their constant drive to establish their superiority over ‘lesser’ species, such as humans, dwarves and elves. Yet many Games Masters probably consider harpies no better than animals, unthinking brutes that can be used to challenge low to mid-level adventurers once creatures such as orcs and hobgoblins cease to pose a threat to them. Unfortunately, this fails to take into account the unique strengths and abilities of the harpy which, when used properly, allow them to be used as opponents for even high-level characters. The Slayer’s Guide to Harpies is designed to provide the Games Master with ideas on how to do just that.