That’s all to prime the reader for the central third of “Jerusalem,” which takes place above time itself, in “Mansoul” (as in John Bunyan’s allegory “The Holy War”), where “The Dead Dead Gang,” a crew of ghostly children led by a girl in a cape made of decomposing rabbits, are having adventures and investigating mysteries. (Their Northampton accents are augmented by “wiz” and “wizzle,” the afterlife’s conflation of “was,” “is” and “will be.”) One advantage of being dead, it turns out, is that you can perceive space-time from the outside, as when the gang encounters the Platonic form of a Northampton landmark:

“The Guildhall, the Gilhalda of Mansoul, was an immense and skyscraping confection of warm-colored stone, completely overgrown with statues, carven tableaux and heraldic crests. It was as if an architecture-bomb had gone off in slow motion, with countless historic forms exploding out of nothingness and into solid granite. Saints and Lionhearts and poets and dead queens looked down on them through the blind pebbles of their emery-smoothed eyes and up above it all, tall as a lighthouse, were the sculpted contours of the Master Builder, Mighty Mike, the local champion.” (That would be the Archangel Michael, who is engaged in an eternal metaphysical snooker tournament that determines the fates of the city’s residents.)

Read that passage out loud, and you can’t miss its galumphing iambic rhythm. Moore, in fact, keeps that meter running for the entire length of the novel, and that’s just where his acrobatic wordplay begins. One chapter takes the form of rhymed stanzas. Another is blank verse, run together into paragraphs but pausing for breath every 10 syllables. A third is a play whose central seam is a conversation between Thomas Becket and Samuel Beckett.

The novel’s most difficult and wittiest chapter is written in a convincing pastiche of Joyce’s portmanteau-mad language from “Finnegans Wake,” and concerns Joyce’s daughter, Lucia, who spent her final decades in a Northampton mental hospital. At one point, the malign spirit of the River Nene tries to persuade her to drown herself: “It is a ferry splashionable wayter go, I’m trold, for laydies of o blitterary inclinocean. But then fameills of that sport are oftun willd, vergin’ near wolf, quereas with you there’s fomething vichy gugling on.” (Note the allusion to Virginia Woolf, who did drown herself.) Lucia declines, and goes on to encounter Dusty Springfield (“Dust’ny Singfeeld”), with whom she has sex while Number 6 from “The Prisoner” looks on. Yes, this is relevant to the plot, more or less.

Books this forbiddingly steep need to be entertaining in multiple ways to make them worth the climb, and Moore keeps lobbing treats to urge his readers onward: luscious turns of phrase, unexpected callbacks and internal links, philosophical digressions, Dad jokes, fantastical inventions like the flower resembling a cluster of fairies — the “Puck’s Hat” or “Bedlam Jenny” — that is the only food the dead can eat. Those who have read Moore’s comics will recognize some of his favorite themes too. Snowy Vernall, who experiences his life as predestined, is in the same boat as Dr. Manhattan from “Watchmen”; there’s a strain of Ripperology left over from “From Hell”; the demon Asmodeus, who appeared in “Promethea,” plays a prominent role here in a different guise.

If cleverness were all that mattered, “Jerusalem” would be everything. Its pyrotechnics never let up, and Moore never stops calling attention to them. Again and again, he threatens to crash into the slough of See What I Did There?, then comes up with another idea so clever he pulls out of the dive. (When the book, in its homestretch, hasn’t yet demonstrated much of a connection to William Blake, Alma Warren effectively engages a detective to work one out, in the person of the real-world actor Robert Goodman jokingly pretending to be a private eye called “Studs.”) The only way to endure “Jerusalem” is to surrender to its excesses — its compulsion to outdo any challenger in its lushness of language, grandness of scope, sheer monomaniacal duration — and confess it really is as ingenious as it purports to be.