Card catalogue

Near-synonym: card index

Source: wiktionary

Ever since the emergence of the written word, humans have scribbled down myths, stories, histories, and natural observations and worked tirelessly to gather and protect these fragments of a shared past. Evolving alongside, in the shadows of the written word, was one of the most versatile and durable technologies in history: the library catalog — a road map for navigating this wilderness of books. The humble yet powerful card catalog progressed slowly and, like countless other important inventions, owes its existence to a number of brilliant thinkers, as well as to the twists and turns of history. From the peculiar and idiosyncratic methods of ancient libraries to far more intricate, comprehensive modern attempts, library catalogs are a tangible example of humanity’s effort to establish and preserve the possibility of order.

Source: wiktionary