The Power of D and D: A History

First edition of AD and D was really a low fantasy game. Magic users had one spell. And when you burn it out, you're back to throwing darts and whacking with a quarter staff. Third edition switched to high fantasy. Your first level cat, this first time you had cantrips. The first time where you generally had more hit points than a monster could do in one attack at first level. You start to see this power curve. Those books added a lot of new functions and features to characters that made them more heroic.