The Superheroic Role-Playing Game
From the introduction:
In 1984, TSR introduced a new Superhero RPG, using the licensed characters and world of the mighty Marvel Comics brand. Suddenly role-players found themselves able to have exciting adventures, taking on the roles of iconic heroes such as the Avengers and all of their members, as well as Spider-Man, Daredevil, and many others. The game was well-received, though it had its share of problems that needed to be “fixed”.
Jump forward to the early 2000’s. Suddenly the Open Gaming License made it easy for anyone to write their own game, and have it instantly playable, using the simple “d20” mechanic.
Mutants & Marvels is an attempt to marry those two ideas, and make it more generic. So, what you have here is an attempt to capture the four-color awesomeness of the old, and infuse it with the streamlined mechanics of the new.