Some of my earliest exposure to audio came from The Fisher Handbook: An Authoritative Guide To Stereo. This relic of the late 60s-early 70s stereo era contains great info about stereo, the nature of sound, and a very cool graphic showing the frequency spectrum that certain musical instruments occupy. There’s a glossary of audio terms, a history of how the LP effected the recording industry and much more. Photos and specs on Fisher components abound.
Back around 1973 a good friend of mine had Fisher gear. I was always in awe of it, it was so out of reach, money wise. $400 for a stereo receiver in the 70s was beyond my piggy bank. Might be the first receivers to have selectable FM channels, just like the car radios of the period did.
Fisher was considered among the best of the manufacturers of gear back then and vintage Fisher can still command some pretty decent prices. I’ve read they’re worth seeking out, if you don’t mind dealing with tubes and updating the electronics. Plenty of online resources if you do a search.
There are apparently several versions of this booklet out there and I suspect mine is a later version. It’s 72 pages of stereo glory, and worth a look if you so desire. Here’s a medium rez (150ppi) 14.4mb file if you would like to download it.