A lot of college libraries will have book scanning machines, its worth asking them.

Aquire a physical copy of the book that you are willing to damage, and carefully dissemble the book into separate pages, trimming off glue on the edge. Then you can scan the pages into pdf format with a scanner. Make sure you get the pages in order. You can use pdf editing software to change page order or flip any that may have been accidentally misaligned in the scanner, and you can combine multiple pdfs into one book, so you can do it in shifts. I’ve only done this on a small scale, but that’s how I did it.

wand scanners are cheap. time consuming though.
you could unbind the book and feed it into a machine but the machines are expensive. i think kinkos can make bulk copies of stacks of papers. too bad you cant scan with their machines.

Find a library selling old equipment and get your own book scanning machine or find an old school hole in the wall type shop. Otherwise one page at a time with an app or a standard home printer scanner (this is the way I go).

Depends on what are the conditions you have to scan them and how good you need your scan to be. The only times I needed to scan a book or documents I had to do it fast and wasn’t worried about quality so my phone and CamScanner app did the trick

Use phone apps for photo-to-text copying.