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 tim 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-pawn majority and go for the endgame.Even though it is a typical \"amateur opening\", Bronznik stands out pleasantly from the romanticized style of the \"Win with\" books. In every position he gets to the bottom of things and demonstrates that in many variations the best moves are still untested - when many beliefe that in our computer age everything can bei found in the omniscient databases.The analyses of various sacrifice games on the kingside are fascinating, and the explanations of positional topics are fundamental and clear. The interplay of more elementary things with more demanding content should ensure that all skill levels get their money\'s worth.