"My name is Wilkie Collins," announces the narrator of "Drood," "and my guess, since I plan to delay the publication of this document for at least a century and a quarter beyond the date of my demise, is that you do not recognise my name."

Au contraire, Wilkie! We know and love you still. Has any thriller ever boasted a better opening sequence than your "Woman in White"? Has any detective story employed multiple narrators more artfully than your "Moonstone"? Has anyone produced so many sinfully entertaining books while maintaining an opium habit that made Thomas de Quincey look like a dabbler?

No, Wilkie, you're still the man. And in fact, your provocative social critiques and nuanced portraits of women make you look considerably more modern than the Victorian aesthetes who thumbed their noses at you. But I admit that, in the opening pages of Dan Simmons's historical thriller, you're in bad shape, Wilkie. In your 40s and already a near-invalid, with rheumatic gout so painful you can hardly see to write. You're living with a woman who's not your wife (you've tried, not very successfully, to pass her off as your housekeeper), and you've got another mistress stashed in private lodgings, and they each want more of you than you have to give.

And, to make matters worse, you're seeing things. A scary gal with green skin and yellow tusk-teeth who wants to fling you down the stairs. And a silent doppelganger — "the Other Wilkie" — who comes when he's least wanted and even writes parts of your books for you. And writes better than you!

Speaking of which, you have the signal misfortune of being best pals with Charles Dickens ("the Inimitable," you call him, not very respectfully). A leading light of the age is our Dickens, which means that everyone around him must learn to live in his shadow or else rage at the dying of the light. And now Dickens ... here's where fact gives way to fiction ... has drawn you into his private mythos, which revolves around a half-Egyptian underworld fiend named Drood. Hard to miss, this fella, with his scarred head and missing eyelids and "a nose that looked to have been mostly amputated in some terrible surgery" and "ears that were little more than stubs." This same Drood, according to a retired police inspector, is London's "least notorious but most successful serial murderer."

You're skeptical, and no wonder. "There is no Drood," you declare flatly. "Only a legend." But then the legend makes himself known to you in truly terrible fashion. And you realize that the only way to be rid of him is to rid yourself of Dickens. Which will have the not unincidental effect of forcing Dickens to acknowledge you as an equal, if not a superior.

Drood, as one might expect, bears a nominal relation to Dickens's unfinished final volume, "The Mystery of Edwin Drood," but it plays out more as a cross between "Amadeus" and "The Usual Suspects." As hybrids go, that has the potential for some horsepower, especially because Simmons, in earlier days, was a much-lauded sci-fi writer, and the pictorial imagination he brought to that earlier genre pays handsome dividends here. In one hallucinatory moment, Collins sees the audience at Dickens's public reading tied by "hundreds of slender, white, barely perceptible cords." Books are "dalmatianed with spattered ink," a nasty black scarab burrows into a human belly "as if flesh were sand" and a man looks down at himself and sees "the hands of a corpse disappearing into chalk."

The most successful of the book's set pieces is in the very first chapter, when the train carrying Dickens and his mistress plunges from the Staplehurst viaduct. This real-life incident becomes almost unbearably vivid in Simmons's hands: "Dickens watched a man stagger towards him, arms outstretched as if for a welcoming hug. The top of the man's skull had been torn off rather the way one would crack an eggshell with a spoon in preparation for breakfast." Equally vivid is the guided tour of "Undertown," a labyrinth of crypts, tunnels, caverns and underground rivers where Drood rules over a small nation of feral children and opium addicts.

It's when Simmons takes his book aboveground that he loses his way — in a forest of factoids. For long stretches, "Drood" is little more than warmed-over biography, larded with the minutiae of London sewage systems and Dickens's Italian travels and his fistula surgery and the names of the dogs who visited his estate and the titles of every last reference work consulted by Collins during the writing of "The Moonstone" ... and then more of same. "Perhaps I have already mentioned ... ," Simmons's narrator murmurs. "Perhaps you also know ... Perhaps I have told you, Dear Reader ... I may have mentioned earlier ..." You have. You have.

And, like the arch-villains he portrays, Simmons gang-presses his characters into historical servitude. "Oh, Mr. Collins!" cries one. "I am deeply honoured to have such a famous writer visit me! I so greatly enjoyed your The Woman in White that was serialised in All the Year Round immediately after Mr. Dickens's A Tale of Two Cities ended." People don't actually talk like this, any more than they say, "Dickens's novel — which I thought rather dreary and stodgy to that point, especially in the person of the cloying and saccharine narratoress named Esther Summerson, did seem to come alive in the penultimate chapters as our Inspector Bucket took charge of the murder case regarding Lawyer Tulkinghorn, as well as in his fruitless but exciting pursuit of Lady Dedlock, Esther's true mother, who was to die outside the city burial ground."

This padding and sock-puppetry come at some cost: The book is halfway over before it feels like it's beginning. (Drood even pauses in the midst of his evil-doing to announce the species of beetle he uses.) Simmons may justify his novel's length as a tribute to the enormity of evil or perhaps to the bagginess of Dickens's own fiction. But "The Mystery of Edwin Drood," had it been finished, would have been one of Dickens's most compact productions, and truth be told, this modern-day "Drood" has less to do with evil than with spite. Specifically, the nastiness that a pair of brilliant men inflict on each other.

A more apropos title, then, might have been "A Tale of Two Egos," which, all in all, is a worthy subject, but not worth the epic length afforded to it. Inside this artery-clogging almost-800-page book is a sleek and sinewy 300-page thriller waiting to be teased out. If only Simmons hadn't left the job to us. — Louis Bayard for The Washington Post