From the introduction: There are worlds full of marvels, where super men and arch-villains battle, green martians and man bats join forces, where wonders of every stripe reign supreme. They are closely guarded, and held within Themselves... only the strongest of needs could ever allow these worlds to intertwine, and even then only for a short time. But this place is not like that: this is a free place, where he-roes and worlds flow and intermingle without limits.