From publisher blurb:
Battle or befriend more than 80 bizarre life forms in this 160-page hardcover creature collection for the Starfinder Roleplaying Game! Every new world and space station comes with its own dangers, from strange new cultures to robotic killing machines to alien predators ready to devour unwary spacefarers. Inside this book, you'll find rules and ecologies for creatures from across the known worlds, plus alien equipment and more.
A robust system for creating your own creatures ensures that your parties never be without weird new aliens to fight or trade with, and racial rules for many of the new organisms let you be the alien, making Alien Archive not just a collection of creatures to kill, but a fascinating menu of creatures to be! Want to play a hyperevolved floating brain? A mighty dragonkin? A silicon-based crystalline slug? Explore the limits of your galaxy and your game with Starfinder RPG Alien Archive!