When Melvil Dewey realized every library organized their books differently, he wondered if he could invent a system all libraries could use to organize them efficiently. Melvil was a persistent (and noisy) advocate for free public libraries. And while he made enemies along the way as he pushed for changes--like his battle to establish the first library school with women as students, through it all he was efficient, inventive, and often annoying as he made big changes in the world of public libraries--changes still found in the libraries of today.