Book excerpt: Daredevil's secret exposed? The identity of Thor passed down to another? A new Hulk? Multiple Spider-Men? Some of the ideas that shook Marvel's foundation got their start right in the realm of remote possibility overseen by the wondering Watcher! But can even Uatu believe his eyes when Jack "King" Kirby rewrites himself and his fellow legends as the Fantastic Four? Plus: from a concept by Roy Thomas, the Avengers of 1958! Collects What If? #7-12.