This book takes a closer look at the Classic mistakes by amateur players include: 1. Moving a piece too often in the opening. This is one of the mainstays which we think relates at least partly to the desire to create something in the opening, when we would be better advised to focus on simple development. 2. Impatience. Sometimes amateur players are too eager to change something when there really is no need. 3. Overgeneralizing. One of the biggest differences I've noticed when comparing professional play to amateur play is that the former is much more about concrete calculation - you go there, we go here and so on - whereas an amateur player will have a tendency to overgeneralize when thinking about a position, perhaps because they are not used to the basic art of calculation. 4. Cutting variations off too quickly. Amateur players do not extend their calculation far enough, and thus superficiality tends to kick in. These and other mistakes are explained in the book. Of course it should be noted that professional players also make these kinds of mistakes.