A commonplace book is a personal treasury of ideas — a place to gather quotations, passages, and reflections that have shaped your thinking. The tradition stretches from ancient Rome through the Renaissance, when scholars like Erasmus and Francis Bacon kept notebooks of memorable passages organized by theme. Over time, a commonplace book becomes a record of an intellectual life: what you’ve read, what moved you, what stuck. This is that tradition, made digital — a living archive of the ideas, texts, and thinkers that matter most.