A Million Open Doors, by John Barnes. He isn't well known, but I like his way of mixing scifi worlds with modern day problems. This novel is about thousands of human cultures on various worlds dealing with intermixing of cultures after instantaneous travel is discovered. In other words, an examination of globalization.
But there are appearances by Spider-Man and Ka-Zar 
This is the second book on heroism, a favorite topic of mine, and it's great stuff. As is their 