How to Handle the Problem of Too Many Classes

During nearly every presentation in which I explain my view of object-oriented programming, there is someone who shares a comment like this: "If we follow your advice, we will have so many small classes." And my answer is always the same: "Of course we will, and that's great!" I honestly believe that even if you can't consider having "a lot of classes" a virtue, you can't call it a drawback of any truly object-oriented code either. However, there may...