Back to the types of books that focus on Superman. This time: Science!
I was a bit surprised at this, but there are several types of books that deal with science and superheroes. Only one, as far as I know, is solely focused on Superman: The Science of Superman, by Mark Wolverton.
Wolverton takes the position that, though none of Superman's powers are achievable for humanity today, the future may be different. He sees the powers as little more than quantitatively different from such natural human abilities as sight, breathing, etc. He speculates that a combination of technical advancement and evolutionary change will make the equivalent of superpowers a possibility. As far as I can tell, this book served as the primary source for the History Channel's program The Science of Superman.
The Science of Superheroes by Lois H. Gresh and Robert Weinberg takes the opposite approach, demonstrating that nothing superheroes do will ever be attainable by humanity. They discuss alien life and the fact that Krypton would have to be gigantic beyond possibility to create a gravitational pull strong enough to make Superman the kind of being in the comics. There may be some influence on the History channel show as well.
The Physics of Superheroes by James Kakalios is a bit of a different book from those two. Kakalios is more interested in teaching physics than in whether or not powers are possible. He's quite happy when the powers are handled with a nod to the way the world works, but he's not hung up on it. He's pleased enough to teach us how to use basic (though extraordinary) Newtonian equations to find out how much force Superman would need to jump the 1/8 mile advertised by Siegel and Shuster in Action Comics #1. (He's not at all concerned with flight, since there's no real physics behind it: he ignores the impossible in favor of learning from the possible).
I like this idea of using Superman, and other heroes--the latter two books are inclusive--as a learning tool. A while back I gave a talk to a middle school about this very thing. I brought up other subject areas: fashion, psychology, philosophy, etc. These are topics that don't have more than one book devoted to them, and I think I'll devote a separate essay to them.
In one sense, these resemble the religious books. They take superheroes as a starting point and then discuss the implications.