The League of Extraordinary Gentlemen is a 2003 steampunk/adventure novel by Kevin J. Anderson. It is a novelization of the script of the movie of the same name, written by James Dale Robinson, which itself was based on the comic by Alan Moore and Kevin O'Neill.
Although differing somewhat from the movie script, and drawing on the original comic, Anderson still noted that "And of course another drawback is that I have to stick to the script exactly as it is, even if I might have different ideas"; as such, the end result is much closer to the film than the comic or a third, independent story.