This was the early version of Google. Using these humble wooden drawers, generations of scholars and researchers, desperate students and cunning spies, despairing parents and fanatical bibliophiles, and every other shape and size of reader delved into the depth and breadth of human understanding.
Something worth considering: Google contains only a fraction of the knowledge once cataloged by card catalogs. Technology has digitized and indexed only that which is easy to digitize and index; most journal articles, newspaper articles, books, scientific papers, notebooks and other written material are still confined to physical forms, and unknown to Internet search engines.
How I miss card catalogs.