The Sound of Rock by Mike Doyle (1993, Paperback, Reprint)

This book is a great reference for all things about Marshall amps, especially the early years. It chronicles the rise of Marshall amps as a rock sound staple. Interesting facts throughout and a lot of info that you don't normally finds when reading about Marshall amps. As a recent Marshall convert, this book gives great insight into a company that actually feels part of the music they help create.