Bring an array of aliens-both weird and familiar-to your science fantasy adventures with Interstellar Species, the newest rulebook for the Starfinder Roleplaying Game! This book offers new options for 7 Starfinder character classes, a system for easily creating your own playable species, and a catalog of around 100 thematic nonplayer characters ready to slot into any adventure, as well as a brand new class: the Evolutionist!