Mystery Monsters Revisited is an unusual entry in the Pathfinder Campaign Setting line. The goal of the book is to transform ten different monsters from real-world folklore and modern legend (so-called "cryptids") into creatures usable in Pathfinder and in the game's official setting, Golarion. The book is a 64-page softcover with full colour interior art that is adequate but not Paizo's best (and I think the cover needed a better inker to add definition to what looks like a coloured pencil drawing). Each of the ten monsters is covered in a six-page section that includes the following topics: Evidence (why the creature is thought to exist), Ecology, Habitat & Society, Campaign Role (how to use the creature in a game), Treasure, Golarion lore, and a full stat block and picture of a unique version of the creature. Each section also includes a brief sidebar about the creature's real-world inspiration. The ten monsters covered are:
* Bunyips (from Australian aboriginal lore), an aquatic mammal that combines features of a shark and a seal. Two new feats just for bunyips are introduced, which is a bit strange. The idea is a bit bland.
* Chupacabras (a modern Puerto Rican legend), bloodsucking creatures that walk on two legs and sneak around at night to feast on livestock and pets. The stealthy nature of the creatures and the fact that they could easily be confused by PCs with vampires or other dangers would make them a good story element for a low-level campaign set in rural areas. A magical weapon, the Chupar Pick, is introduced.
* Death Worms (the Mongolian "Olgoi-Khorkhoi"), which, as the name implies, are gargantuan subterranean worms that live in desert areas and can spit acid and electricity. Despite the added attack styles, Pathfinder has enough giant worms and I don't think much is added here. This section includes a new magic item to see creatures moving underground, Vitreous Goggles.
* Mokele-Mbembe (a Congo legend), a massive saurian that is basically a swamp dinosaur with long spines down its back. Again, a bit bland. A new magic weapon, the Mokele-Mbembe Tail Whip, is introduced.
* Mothman (a West Virginia legend), a strange, unearthly winged humanoid that appears just before terrible disasters for an inexplicable reason. This was the first entry in the book that really caught my eye as something that would be fascinating to add into a campaign. The new magic item introduced here, a Mothman Memento, is also well done.
* Sandpoint Devil (based on the Jersey Devil), a winged-horse that stands on two legs and has demonic teeth and horns. I'm running Rise of the Runelords right now which of course has Sandpoint as its setting, so I'm partial to this entry.
* Sasquatch (Bigfoot), a forest-dwelling apelike creature. A cursed item called a Sasquatch Skull is introduced here.
* Sea Serpents (from many cultures), enormous snakes large enough to sink entire ships. Could be interesting as a major storyline in an aquatic-themed campaign. A new magic weapon, the Serpentseeker Bow, is introduced.
* Water Orms (the Loch Ness Monster), lake-dwelling saurials that are enormously reclusive.
* Yeti (the Abominable Snowman), alpine beasts with sharp claws and teeth. I really liked the lore added by the book here, as they portray Yeti as the nobel guardians of portals to dangerous extra-dimensional lands like the Lovecraftian Leng. A magic item called Leng Tea is introduced.
The book does a good job emphasizing that these legendary creatures really need to be built up over a period of time in a campaign. If you just drop a random Sea Serpent attack in while the PCs are on a boat, then Sea Serpents are just another monster. But if you depict sailors and dock-workers growing increasingly frightened over the course of several sessions by the legendary Ashen Worm, then it means something when/if a fight actually takes place. In other words, these creatures aren't meant for random encounters but are instead best used as driving forces for story-lines that can include investigation, tracking, red herrings, scam artists, and more. That being said, only a couple of the creatures listed in the book really struck me as elements I'd love to bring into a campaign. Many left me feeling "meh." So in sum, I'd say that Mystery Monsters Revisited isn't a *bad* book, but it shouldn't be a high-priority for readers.