Technically, the 'complete set' is 4 books which includes "the electromechanical era" edition.
Oops, didn't know about that one and too late to modify. 
Correction: an almost complete set...
So why did he do 'the electromechanical era' edition when the 3 books I have cover the 1930's until now? Does it repeat stuff in the other books?
He got much better photos as some of the pics in the first book were of unrestored machines, it also has more info from different designers, artists etc.
