I have both of Mr. Jones's books, the 3rd edition Valve Amps and the newer Building Valve Amplifiers. I find them both worth every penny. Very informative. Unfortunately my math skills are lacking and I'm having to refresh the old noodle. I found that Steve Benches explanations on loadlines was a bit easier for me to understand, but MJ goes into much more detailed explanation of the "why" something is done.