How libraries managed borrowed books before computers?

Books had a pocket glued onto the fly page. The pocket contained a card with the book name on it. When you borrowed the book, the librarian removed the card and wrote your membership number on it, and retained the card. The “return by” date was stamped on the pocket.

The book you were checking out had a little pocket glued to the inside of the cover that held a card with the book name on it. The librarian would write your number on the card and placed it in their filing system. They would then write or stamp the due date on the pocket of the card.

https://media.istockphoto.com/photos/library-book-due-date-g...

I can provide part of the answer for libraries, but my memory is sketchy. I worked in a major university (U.S.) library in the 1970s. Each book had a paper card in a sleeve glued into the inside back cover (or was it the front? doesn't matter). The card had the author, title, and filing number (Library of Congress system) and some indication if it was one of several copies in the collection. (These were mirrored by an identical card in the main card catalog).

When a student or faculty member checked out the book, we had a photocopy machine that recorded the book card info and the user's photo ID. The current date was on there too. The photocopy output was maybe 3-in by 8-in (not full size sheet) and was on a stiff type of paper. I distinctly remember using a manual sorting device at the end of the day to alphabetize the photocopies -- it was a narrow board maybe 2-ft long, with plastic flaps for the letters of the alphabet, so one could easily slide the photocopies under the correct letter of the alphabet (by author last name, as I recall).

So, if someone could not find a book on the shelf, it was fairly easy to find who had it checked out and send them a recall notice, if they had checked it out sufficiently long ago. I do not recall whether or how routine overdue notices were sent (maybe there was a policy that you could keep the book out until recalled or the end of the current term, whichever came first -- renewals were also possible).

I wish I could remember more details. I spent more time working in the stacks area (supervising the re-shelving of returned books) than at the circulation desk.

I was also there when the first pass at computerization was done - we had to manually affix barcodes to every book as it was re-shelved, with the same barcode on the card in the book, for adding to the database. Once books were barcoded, the circulation became computerized, as I believe the user IDs also had barcodes -- no more photocopies and no more manual alphabetizing. This was pretty novel at the time, we even had T-shirts made with a large barcode symbol as the graphic on the T-shirt, I don't remember if it had a funny caption or not.

Many descriptions of old systems here: https://boards.straightdope.com/t/how-did-libraries-keep-tra...

“How did ‘X’ work before computers?”

Recently I saw someone ask how vinyl records were ‘decoded’.

It’s good that young people are asking these questions, but it does feel odd to be part of the last generation to have grown up in the pre-digital age.