The graphic novels are literally as good as the movie was bad. I can't wait for volume 3.
Needless to say the book is far more true to the actual characters than the movie was. Allan Quartermain is a hapless Opium adict. Minna is a willful woman of great mental constitution (hardened by her encounter with the being only refered to in the books as "the foreigner") but no supernatural abilities. Nemo is an embittered England-hating loner who's reduced his crew to the bare minimum (2 men: Ishmael & Broad Arrow Jack). Dr. Jekyll is unfortunately slipping away as his metabolism has addapted to no longer need the potion to change & as Hyde's evil has grown he grows greater & more powerful as Jekyll slips away (Hyde is by the by implied to have been Jack the Ripper before running off to Paris following Jekyll's suicide attempt; this fits the original book's timeline & the fact that Hyde's deeds aren't directly described). Griffin is still the invisible man & just as must the chauvinist monster as always. The mob killed an albino-experiment of his.
Dorian isn't in the books (so far), but artwork implies him to be a former member of some incarnation of the League. Tom Sawyer is never addressed & in order to avoid association with the blight of the movie Alan Moore has given a No-Sawyer-Guarantee for all future Volumes of the League of Extraordinary Gentlemen.
Also the Fantom plotline was an invention for the movie. The actual Phantom of the Opera is implied (in the Almanac in the back of Vol.2) to be a member of Les Hommes Mysterieux, the French incarnation of the League, but thats it. Minna finds him very distasteful in large part due to how... reminiscent he & his relationships are of one of her previous relationships :)
Volume 1 actually focuses on an Air War (appropriate for the era & pulp genre) being engineered by one of England's greatest crime lords to destroy his criminal rival. I'm giving spoiler warning now...
The two criminal lords are none other than James Moriarty & Dr. Fu Manchu. The League never sees "M" until after he finishes with them, only relying through their liason Champion Bond (infact Minna assumes that "M" is Mycroft Holmes). Moriarty claims to no longer remember whether he's the head of British Intelligence masquerading as the Napolean of Crime, or the Napolean of Crime masquerading as the head of British Intelligence... & it no longer matters.
