I have the first three and volume 3 is definately my fav. Heaps of great pics of every machine made from 1990 on, heaps of interviews with the designers, programers, artists and sound guys that brought these great games to us. A truely great insight into the pin business. A must for all collectors of the era!
Just run out and buy it! Oh sorry they are not printing any more 

Sorry just had to rub that in guys