Knowledge is power, and nowhere has it been more carefully gathered and guarded than in libraries. From ancient temple archives and the clay tablets of Ashurbanipal to the glittering court library of King John V of Portugal—one of the great lost collections of Enlightenment Europe—libraries have shaped how knowledge survives. We’ll trace their story through medieval scriptoria, Renaissance and royal collections, and the rise of national and public libraries that opened the stacks to wider publics. Along the way we’ll ask who libraries have served, how they’ve balanced preservation and access, and why, in an era of search engines and e-books, they remain at the heart of learning and community life.