Software marches forward; each new piece is better than the last in every way! Not quite... it's a bit more subtle than that. There are patterns in the history of our industry: each tool or practice is a reaction to something before it. By paying attention to the pattern, and to the types of reactions, we can better understand our history and our current tools' place in it. More importantly, we can avoid repeating the mistaken reactions that our predecessors have had to new tools.