If you're looking for a major contribution to an audiophile's library try The Complete Guide to High End Audio by Robert Harley. Now in its 5th edition I occasionally open my 1st edition and never cease to be amazed.
Descriptions of every component, not just what they do but how, down to the power supply and basic circuitry;
The importance of every component including power cords, interconnects, speaker cables, and even vibration control efffects and the importance of a good equipment rack;
Speaker placement and room acoustics, with even the math to work out your room modes, enough math to calculate bass trap dimensions needed for the frequency range you want to treat;
And a whole chapter devoted to the importance of listening skills, how to learn to listen well, and a glossary of audiophile terms;
And that's just skimming the surface.
One could easily read everything posted on this site, and every other site, and in Stereophile, and all the other audio publications, and still not learn as much as reading this one book.
In fact, now that you mention it, about the only negative thing I can think of to say about it is its not very impressive as a coffee table book.
