Previous viewers have noted that "GURPS Fantasy Bestiary" was nothing like TSR's monster manual, i.e. it does not include fantasy races like goblins and minotaurs, and it doesn't include made-for-gaming creatures like beholders. Instead, it presents samplings from various mythological traditions (European, Chinease, even rural America). Unlike previous viewers, I applaud this approach heartily. The fantasy races were best covered in another book where their uniqueness could receive the proper attention, and most made-for-gaming monsters are agonizingly lame. Any of you AD&D players remember the Flumph? My point exactly.
With this book, players can go toe-to-toe with creatures that have a solid mythological history, but are not necessarily so cliche that the fight becomes an exercise in dice rolling. Perhaps your players have heard of the bunyip, but do they know what it can do? How about the hodag? The Chon-Chon?
My number one gripe against this book is the large numbers of unique monsters in it, such as Cerebrus and Scylla. While some of these could be used as guidelines to create breeds of monsters (as is often done with, say, the hydra) others seem to be there just to take up space. The Scylla of myth was more of a force of nature than a foe to be fought, why give it valuable space in a book of foes to be fought?
Aside from that, this book provided me with considerable food for thought in designing fantasy adventures. It even includes chapters on monstrous plants and dragons (although the latter may be outdated with the publishing of GURPS Dragons). I recommend it to any GURPS fantasy GM.