Welcome back for 2025! Worldbuilder's Book Club is a reading challenge for writers, tabletop gamers, and others interested in reading non-fiction with an eye to its potential for informing your fictional worlds, whether you're working your way through a stack of books you've already compiled for research or you're reading a varied selection of titles to generate ideas. This challenge is intended for deepening both realistic and fantastic worlds by reading twelve books covering different aspects of society and the natural world during 2025.