How would I find people who might be interested in old computer technology books?

I found some by posting to Cragslist.

Depending on where you are, there might be a computer museum…
https://en.wikipedia.org/wiki/List_of_computer_museums

Computer museums—good idea! I’ll check. Thank you.

How about old motherboards, CPUs, video cards? Mine are headed to the next e-waste event.

It probably depends on what they are. Some people may be interested, depending on what it is.

There are also electronics recycling businesses that will sort through things given to them. They vary a bit in how likely they are to do what with everything.

e.g.

http://www.seattlecomputerrecycling.net/