Not sure about all three - but this one has to be among them. It was a sourcebook for Champions, that from a gameplay side had a huge number of characters heroes and villains for a GM to use. But it is also one of the greatest game authors chronicling his campaign. It is also one of the best GM advice books ever written - there are a lot of thing in there that are standard now, but when this was published it was groundbreaking - I'm speaking of course of Aaron Allston's Strike Force (the original)
This is one of mine, along with the original Delta Green sourcebook (for Call of Cthulhu) and Bookhounds of London (for Trail of Cthulhu).