First, ask yourself this: Are you really prepared to take on Jonathan Strange & Mr. Norrell, a 782-page bruiser of a novel about 19th-century magic? Do you have the stamina to pick your way through scores of verbose footnotes in a microscopic font? And honestly, if you're going to ascend a mountain of dense, detailed prose, shouldn't you first tackle ''War and Peace''?
More than ten years in the writing, Susanna Clarke's immense, intelligent, inventive, arid, and exhausting debut offers up a fictional history of English magic told through the biographies of two magicians, fussy Mr. Norrell and intuitive, reckless Jonathan Strange. The narrative begins with great charm and promise: It's 1806 and magic seems to have disappeared from England. So-called magicians gossip, theorize, and hold meetings, but they don't practice their art. As one of them puts it, ''Tradesmen prosper, sailors, politicians, but not magicians. Our time has passed.''
Actually, he's wrong. Curmudgeonly, mysterious Mr. Norrell, who resides alone on a remote Yorkshire estate, issues a challenge: He will perform magic, provided that when he does so, all theoretical magicians in Yorkshire agree to drop their claims to the title (most, but not quite all, do). Shortly thereafter, Norrell brings to life the statues in a local church. The stone figures jabber, complain, wave their arms, and recount tales of long-ago murders. For better or worse, the renaissance of English magic has begun.
Norrell, alas, turns out to be a notorious bore (and a sadly lackluster character): ''He hardly ever spoke of magic and when he did it was like a history lesson and no one could bear to listen to him.'' Jealous of his newfound position as England's premier magician, he buys up books on magic so others can't study them. He finds no one to rival his powers until a genial, talented neophyte named Jonathan Strange (who took up magic to impress his future wife) appears on the scene in 1809. They have some serious philosophical differences, but Norrell accepts Strange as his pupil.
In the endless, plodding middle section of this huge book, Clarke inserts her protagonists, ''Zelig''-style, into real historical events like the Napoleonic Wars, where they cast spells to thwart the French. Sadly, there's no likable Harry Potter or Frodo to coax us through these prolonged dramatic detours; Clarke keeps her central characters -- and thereby her readers -- at a cool arm's length. Eventually, the two magicians fall out and begin casting nasty spells on each other, even as it becomes horribly clear there are evil supernatural forces abroad that they must team up to defeat.
Reading about magic should never be a chore; what, after all, is the point? Clarke is a restrained and witty writer with an arch and eminently readable style. But it's not a style built to sustain a big, sweeping narrative like the one she's produced. Hammier, sloppier, more passionate prose would have done a better job on this humongous canvas. Wholly original and richly imagined, ''Jonathan Strange & Mr. Norrell'' turns out to be more admirable than lovable.