The Colle-Koltanowski System with d4, Nf3, e3, Bd3, c3, 0-0, Nbd2 is very popular among club players.
White builds up a kind of "fortress", but at the same time prepares to hand out some blows himself, e.g. the typical bishop sacrifice on h7. In other cases he can rely on the characteristic queen-side pawn majority and go for the endgame. This is a book about a typical "amateur opening", but nevertheless Bronznik refuses to go for the "Winning with" approach.
He does very thorough research and shows that, in fact, in many lines the best moves are still untested.
Fascinating is Bronznik's analysis of the various sacrifices on the kingside (Bxh7+, Bxh6 and so on), and his explanation of the positional themes is clear and deep. Due to the blend of basic with advanced material this book should be useful for average players, as well as for masters.