Note: these books are four or five years old and possibly out of date. I don't really grok hardware...
Intel Corp.; 1986; ISBN 1-55512-024-5;
Pin connections, timing, waveforms, block diagrams, voltages, all that kind of stuff.
Messmer, Hans-Peter; Addison-Wesley; 1993; ISBN 0-201-62424-9; 1000 pp.
JH: "Covers the more recent stuff like EIDE and PCI."