whitewiz,
I you are interested in an introductory book on power power amplifier design using discrete components (as opposed to IC design), the following book is very good:
"Audio Power Amplifier Design Handbook" by Douglas Self
The book concentrates mainly on classes A, AB, B, G, but it gives definitions for the following classes:
A, AB, B,C, D, E,,G,,h, S
For Class D (Switching) amplifiers, I would recomment searching the web. There are lots of articles out there.
Regards,
Kral