I usually stick to the service manuals published by the manufacturer. I tried stuff like the Chilton's manuals when I was an ignorant teenager, and they just had enough information to get me to start a job, then when I took something apart, it didn't look like the picture...
Here's the manuals I have for my vehicles:
1981 Buick Service Manual
1981 Fisher Body Service Manual
all 1981 Buick parts manuals
1986 Chevrolet truck service manual
1986 Chevrolet truck body service manual
1986 Chevrolet truck electrical service manual
I don't have any service manuals for The Beast, never needed them.
-Jay