From the introduction: Welcome to the Marvel Universe! This was a world much like our own until about the 1940s. Then, it diverged somewhat drastically. Superhuman beings have sprung out of the woodwork. Some products of government experiments, some magically imbued, others remnants of alien invasions, and even some hated mutants, the world is full of superbeings. Some heroes... Some villains... And some in between... User summary: All of the pages in the PDF have different sizes.