If you are interested in obsolete technologies, you might like to know about a publisher in the UK, Camden, camdenmin.co.uk who specialise in that sort of thing. (They started with steam, but expanded.)
If you want a parts list for a Gnome radial, how to build a Tesla turbine, or how to rig a DH.9, that's the place to look. Mostly mechanical, but at least some electrical material. (No connection, other than a customer from time to time.)
The "steampunk" section looks as though it might be relevant; steampunk is close to Pratchetty.
I learned what "See Librarian" really meant from a wonderful homage to Tennessee Williams called "The Kindness of a Stranger". The homage is by cult film director John Waters, published in the New York Times Sunday Book Review in 2006.
I wanted these "see Librarian" books — and I wanted them now — but in the late 1950s (and sadly even today), there was no way a warped [12-year-old] adolescent like myself could get his hands on one. But I soon figured out that the "see Librarian" books were on a special shelf behind the counter. So when the kindly librarian was helping the "normal" kids with their book reports, I sneaked behind the checkout desk and stole the first book I ever wanted to possess on my own.
Alas, true on both counts. Perhaps TI was trading on the "Texas" ranch connection. The bindings were a brown/yellow color, presaging the later adoption of a brighter yellow for TI books that still is in use AFAIK. They were hard to obtain (for free), and only from TI factory reps or FAEs. TI SOLD most of them for a pretty penny. I got mine when I worked in the Motorola Comm Division Research labs in the late '60s. Although Mot was a TI competitior we had a very good relationship with them as the industry was pretty small then.
BTW, at one time my catalog collection included EVERY year's HP test gear catalog. In the same "pruning" that resulted in the loss of the TI books, I kept only the late '90s to the last one pre-Agilent. Still have those.