You can never have too many monster books in my mind. Even I use one or two per book and my players are surprised or go "what in the hell is that!?" then it is money well spent. Monsters have taught me so much over the years. Monsters lead me to Greek Mythology. Monsters helped me learn how to write code to create databases and then later helped land a DBA job while I was still in school. One day I'll update my old Access95 Monster Database, but it will have be later.
Blood & Treasure 2nd Edition Monsters is for the Blood & Treasure 2nd edition game, but can be used with any Old-school game. The system is a mix of Swords & Wizardry and AD&D 1st Ed/OSRIC so reading the stats is really easy.
215 pages, over 600 monsters. Color cover, black & white interiors.
This one has all the usual suspects from the various SRDs and that is fine for me really. There are some new descriptions and there are new monsters.
There are things in this book that make it more worthwhile than just monster stat blocks. There are a number of conditions and definitions ported over from 3.x OGC that are very welcome additions to the "OSR Ruleset". There are guidelines for Monsters as a Character Race which are quite nice.
Another import from 3.x are Monster Templates. Now you can a Celestial Gnome or a Draconic Goblin among other things. Really expands your creature database.
There are even four mini-adventures included.
Not at all bad for just under $10. Highly recommend!