The League of Extraordinary Gentlemen: The Absolute Edition By Alan Moore and Kevin O'Neill<br></br>Top 10: Book Two By Alan Moore, Gene Ha and Zander Cannon

Hack hyper-drive: Nick Hasted marvels at the vision and stamina of a comics maestro who returned 'From Hell' to a brighter place

Alan Moore is one of the British underground's great figures, a wild-haired, dragon-ringed associate of Michael Moorcock, Iain Sinclair and other keepers of the Blakean flame. He is a self-proclaimed magus, writing, since his 40th birthday 10 years ago, with the aid of visions and divine communications. He occupies the lonely post of Northampton's Greatest Novelist, thanks to his single effort at full-length prose, Voice of the Fire (1996), a millennia-spanning dissection of his home town. And, in his principal role as comics' most revolutionary writer, he is a formal innovator, puppeteer of pulp iconography and creator of functioning, fantastic worlds with few peers.

With the award-winning, bestselling Watchmen (1986) - leader of the new breed of "graphic novels" that briefly made comics socially acceptable - he reimagined the superhero genre in its entirety, reweaving every strand of society, from mass media to nuclear dread, around the fact of their existence, with obsessive rigour and visceral conviction.

Moore was almost famous then. And yet in the 1990s, he seemed almost to vanish. Bull-headedly refusing employment by comics and publishing industries that he saw as too often immoral, he created his greatest work, From Hell, a meditation on the Ripper murders, the 1880s and 1980s which took 10 years to complete, in a state of self-imposed exile. The Victorian weight of that work, dark with images of stone, soot, shadows and blood, seemed to be crushing him. With the claustrophobic chapter he built around the Ripper's night-long butchery of his last victim in a furnace-hot room, he pushed into a place not every writer returns from.

But having stared into the fictional pit, the Moore who has re-emerged in the past few years has written with a free, relieved lightness, a revived sense of the fun and sparkle of comics and books. In 1999, he began scripting five monthly comics at once, accessing what he termed "hack hyper-drive" to sustain this Big Bang of freshly struck worlds. Promethea - about the myths behind Wonder Woman, teenage girls, art, magic and evolution - is the conceptual core of this new Moore. But The League of Extraordinary Gentlemen best represents his easy spirit.

Its idea is beautifully simple. In 1898, a threatened British Empire brings together Mina Harker (Dracula's survivor), Captain Nemo, Dr Jekyll and especially Mr Hyde, Allan Quatermain and the Invisible Man. Together, they brave Fu Manchu in his Limehouse lair, and steal back the Cavorite (the means of lunar flight in Wells's scientific romance The First Men in the Moon) with which he means to air-bomb London. But the "M" the League answer to turns out not to be, as they suspected, Mycroft Holmes, but Moriarty, hunched survivor of his battle at the Reichenbach Falls with the more famous Holmes (beautifully restaged in flashback), and a murderous secret employee of the British state, who emerges from his own West End base to bombard Fu Manchu's East End.

Where From Hell mired itself in Victorian darkness, this is the era's Technicolor flipside, a tribute to the vigorous fictions the age also birthed. Moore may be noting, too, that the superheroes and villains with which comics are often dismissively associated have always been a potent part of literature. A glimpsed 1787 picture on the walls of the MI5 HQ in Moore's altered England shows an earlier League of equally memorable, fantastic characters - an aged Gulliver, the Scarlet Pimpernel, Dr Syn, Fanny Hill and Natty Bumpo.

Nor is that the end of the allusions. An omnivorous reader, Moore makes his pages teem with characters who would have been "alive" in 1898, from Verne's Air Pirate Robur to a decrepit Artful Dodger. The era almost seems to buckle under the quantity of its popular fictions as they jostle for space, a vivid world at odds with, if often springing from, the grey grind of everyday Victorian existence. If Moore believes, as Promethea suggests, that art is as real and essential as more concrete creations, then this cross-section of the Victorian imagination helps make his case. All the more so, because he makes no false distinctions between "high" and "low", reputable and not. In one sly sequence, the Invisible Man is discovered as the cause of mysterious pregnancies at the Correctional Academy For Wayward Gentlewomen of Miss Rosa Coote, a Victorian porn character. In a stray panel we see a young Olive Chancellor, of Henry James's The Bostonians, being fervently caned by Katy Carr (of What Katy Did Next). Fellow pupils include Pollyanna, and the future mother of Rebecca of Sunnybrook Farm. All were contemporaries, all have to muck in in this mental landscape. As he did with superheroes in Watchmen, Moore here processes the whole of Victorian literature, to make a coherent, meaningful world.

A cheaper paperback edition was published last year, priced at £13.99. But should you have a spare £75, this slipcased, two-volume deluxe set does have advantages. First, as it is larger, it fills more of your vision, making the sheer spectacle of, say, the Nautilus's first, full-page eruption from the sea, or the air war over London of Moriarty and Fu Manchu, more thrilling - like a wide-screen print, not one cropped for TV. The importance of Kevin O'Neill's beautiful art is confirmed by this edition's other extra, a volume containing Moore's script. Written as a sort of letter to the artist, it is a mixture of stage directions, dialogue, conversational story-telling, and passages of passionate literary description, all to convey images it is O'Neill's task to "act" out. Compared to the script for From Hell, which worried over the position of every object in every panel, this more relaxed work shows comics' true, hybrid nature.

There are other extra "treats" in all editions, from an illustrated Allan Quatermain novella to a Paint-by-numbers Picture of Dorian Gray, confirming a fully imagined environment. But to see this element of Moore's mind at its most over-heated, you may wish to turn to another of his new creations, Top 10.

The conceit this time is equally simple and effective: setting a Hill Street Blues-style, busy police precinct series on a planet where everyone has super-powers. An investigation of the murder of Norse god Baldur, only for him to revive at day's end as his death is a recurring archetype, is a typically synapse-fusing case. But it is the detail at the back of brimming panels, or in asides, that delights: the superhero sanitary towel ads ("Feel confident even in the most undignified battle positions!"); stretchable superheroes like Plastic Man as literal rubberneckers at a road crash; the mother who is a Human Lie Detector; the advertisement for a TV series, Businessman: "You'll believe a man can't fly!" The fertility, funniness and internal logic of Moore's imagination here is deeply pleasurable.

These are not his deepest works: they will not lodge unwelcomely at the back of your mind, as From Hell does. Like his pulp sources, they concentrate instead on strong characters (Mina Harker, traumatised by Dracula, but primly tough in a way her time distrusts, is especially appealing), and strong sensations (the entrance of the 10ft, tombstone-toothed Mr Hyde). But as reminders of why reading and thinking are such vital fun, they are hard to beat.