Download right Here
Under Core Rules Referee Resources
This free download available from the Swords & Wizardry Website is awesome & bold. The book itself is a massive 170 pages long & includes monsters from Aardvark To Zombie Ravens. The handy thing about this collection of monsters is the encounter charts which are keyed to Challenge level & environmental conditions that are included with the download.
More then a few of the monsters are in fact very science fantasy friendly. They have a weird science fictional edge. As with all swords & wizardry they're very professionally done blurring the lines between fan & pro. that we've seen before in the OSR movement.
Because of the massive page count, the awesome lay out, & the crisp presentation this is a must have for any dungeon master. Seriously your not going to run out of monsters for Any encounter any time soon. Because of the challenge rating on these monsters it makes converting them over to say Dark Dungeons or your favorite retro clone a snap. Need a monster for an adventure in a swamp for a 4th level party & bang you've got one! The monsters are interesting as well, all of your old favorites are there but there are some new faces as well. Stuff like this
To something like this :
If your already a D& D dungeon master then by all means give this one a look over. It will not disappoint at all. A bit of advice as well is to separately print out the encounter charts & have those on stand by for wilderness or urban encounters. There's even a few for planar encounters as well!