Commonplace books (or commonplaces) are a way to compile knowledge, usually by writing information into books. They have been kept from antiquity, and were kept particularly during the Renaissance and in the nineteenth century. Such books are similar to scrapbooks filled with items of many kinds: notes, proverbs, adages, aphorisms, maxims, quotes, letters, poems, tables of weights and measures, prayers, legal formulas, and recipes.
Entries are most often organized under systematic subject headings and differ functionally from journals or diaries, which are chronological and introspective.