From the introduction:
Superheroes.
A concept that could have, in a different world, inspired and entertained generations of young (and not so young) children. But here, capes (really, men and women with no power more impressive than a good physical condition) have become just real enough for the fantasy to crash against the brutality of the 20th century. Despised as vigilantes and made illegal by the government, their number has dwindled, and for all but a few crazies their past exploits are mostly something to chat about during awkward reunions. No supervillains left either, unless you count Nixon and his four successive mandates. Along with the visionary industrialist Adrian Veidt, another retired superhero, the President is undoubtedly the one to have benefited the most from this strange alternate history.