Thomas Pynchon is known as the most seductively difficult of living novelists. He has the kind of following that only a bearer of esoteric knowledge can attract — not just readers, but disciples, who find in books such as “Gravity’s Rainbow” (1973) a cranky, erudite scripture for our time. Such fans love to apply their homemade hermeneutics to the mysteries with which Mr. Pynchon’s novels are carefully seeded. Who or what is V., the multivalent object of desire in “V.” (1963)? Who is behind the Tristero, the ancient conspiracy that ensnares Oedipa Maas in “The Crying of Lot 49” (1966)? Precisely because there are no final answers to these questions, they admit endless interpretation. For Mr. Pynchon, indeed, our world is nothing but a theater of frustrated interpretations, of meanings deferred and clues undeciphered. Yet he always holds out the hope that somehow, to a chosen few in an indefinite future, the mystery will be revealed.

After reading “Against the Day” (Penguin Press, 1,085 pages, $35), however, it is hard to avoid the conclusion that Mr. Pynchon’s difficulty is really just the costume worn by his simplicity. The complexity of his novels, and of this eagerly awaited sixth novel in particular, is really a matter of simple multiplicity: They are stuffed to bursting with oddities, so that the reader moves through them at the halting pace of a rubbernecker. In “Against the Day,” which spans the quarter-century between the Chicago World’s Fair of 1893 and the end of World War I, Mr. Pynchon dispenses his oddities in double fistfuls. We get a hot-air balloon crewed by boy adventurers, a dynamite-toting anarchist, a mysterious fourth dimension, a crystal lens that splits time, a ship that can sail through sand, the legendary Tibetan kingdom of Shambhala — and that doesn’t even begin to exhaust the list.

The list — there is the glory, and the downfall, of Mr. Pynchon’s fiction. The author himself, in the gnomic blurb he wrote for “Against the Day,” advertised it with a giant list: “The sizable cast of characters,” he promised like a sideshow barker, “includes anarchists, balloonists, gamblers, corporate tycoons, drug enthusiasts, innocents and decadents,” and on and on. And the novel keeps that promise, to a fault. It reads like a list, at times like a list of lists — for Mr. Pynchon is never unwilling to interrupt the plot, such as it is, with a bravura catalog. Here is an example taken almost at random, a description of a jury-rigged laboratory:

The shelves and bench-tops were crowded with volt-ammeters, rheostats, transformers, arc lamps whole and in pieces, half-used carbons, calcium burners, Oxone tablets, high-tension magnetos, alternators store-bought and home-made, vibrator coils, cut-outs and interruptors, worm drives, Nicol prisms, generating valves, glassblowing torches, Navy surplus Thalofide cells, brand-new Aeolight tubes freshly fallen from the delivery truck, British Blattnerphone components and tons of other stuff Chick had never recalled seeing before.

How you feel about a passage like this is a good indicator of how you will feel about “Against the Day,” and about Mr. Pynchon’s fiction in general. If you are dazzled by the sheer number of odd items Mr. Pynchon accumulates here, by the range of his knowledge and curiosity, you will be still more dazzled by the unstoppable proliferation of the novel, which adds new characters, new plots, and new settings until the very last of its 1,100 pages. Mr. Pynchon writes as if his pleasure in trundling the hoop of the novel from place to place were unlimited, and as if the reader could not help but share it.

As a result, trying to summarize the plot of “Against the Day” is pointless, and gives no real sense of what the book is like to read. Reduced to its absolute skeleton, one might call it the tale of the four children of Webb Traverse, a bomb-throwing Western anarchist, who is assassinated by outlaws in the pay of the evil plutocrat Scarsdale Vibe. Whether and how to avenge Webb’s death is the question that propels his children through the novel: Frank, a gunslinger who joins the Mexican Revolution; Reef, who ends up in decadent, spy-riddled Eastern Europe; Lake, the only daughter, who perversely marries her father’s murderer; and above all Kit, who goes to Yale and enters the world of advanced mathematics, from which much of the novel’s dippy mysticism is drawn. And that is not to mention the Chums of Chance, as the balloon-riding juvenile heroes call themselves; or Yashmeen Halfcourt, the math genius pursued by a Tarot-card-obsessed organization named T.W.I.T.; or the hundreds of other characters and historical events that “Against the Day” assimilates as it grows omnidirectionally, like an amoeba.

If, on the other hand, you find that Mr. Pynchon’s catalog of lab instruments adds up to less than the sum of its parts; if the sheer feat of touching on every major historical event from 1893 to 1918 seems sterile in its virtuosity; if the kind of ingenuity manifested in Mr. Pynchon’s famously weird character names (in the new book we meet Professor Vanderjuice, Alonzo Meatman, Ewball Oust, Ruperta Chirpingdon-Groin) strikes you as childish, and eventually sets your teeth on edge — then you will experience “Against the Day” as a neon-lit desert, full of distractions but devoid of sustenance.

For the writer who lives by the list must die by the list, and Mr. Pynchon, in pushing the form to its limits and beyond, demonstrates what a list-like novel cannot do. Multiplicity, it turns out, is not the same thing as complexity: Complexity requires syntax, and syntax is just what the maker of lists must forswear. Human meanings — psychological, social, spiritual — require other kinds of structure than the infinitely repeated “and” of the shaggy-dog story. That is why Mr. Pynchon’s meanings, in “Against the Day” as in his better books, are finally inhuman, Manichean, utopian, and dystopian. He believes in conspiracies, not histories, including the individual histories that the novel was invented to tell.

The gaudy names Mr. Pynchon gives his characters are like pink slips, announcing their dismissal from the realm of human sympathy and concern. This contraction of the novel’s scope makes impossible any genuine comedy, which depends on the observation of real human beings and their insurmountable, forgivable weaknesses. What replaces it is parody, whose target is language itself, and which operates by short-circuiting the discourses we usually take for granted. And it is as parody — in fact, a whole album of parodies — that “Against the Day” is most enjoyable. Mr. Pynchon takes on some of the distinctive genres of his chosen period and reduces them to absurdity: the Oxford novel (Yashmeen Halfcourt is a version of Zuleika Dobson), the science-fiction epics of Jules Verne, the boys’ adventure serial, the cowboy dime-novel.

Yet “Against the Day,” of course, has higher ambitions than parody. It is also a novel about political violence, set during a period when Anarchist terrorism filled the headlines the way Islamist terrorism does today. The story takes place during the run-up to World War I, and all the characters are haunted by omens of the catastrophe to come. Those hauntings are themselves clearly haunted by Mr. Pynchon’s memory of the attacks of September 11, 2001, which appear in the novel in a powerfully distorted, dream-like form:

Just at the peak of the evening rushhour, electric power failed everywhere throughout the city, and as the gas-mains began to ignite and the thousand local winds, distinct at every street-corner, to confound prediction, cobblestones erupted skyward, to descend blocks away in seldom observed yet beautiful patterns …The noise would be horrific and unrelenting, as it grew clear even to the willfully careless that there was no refuge.

“Against the Day,” then, will inevitably be read as Mr. Pynchon’s contribution to the genre of post-September 11 fiction. Yet by comparison with the other major novelists who have addressed this theme, he displays a surpassingly crude moral imagination. This is a novel, after all, in which most of the heroes are proud terrorists, committed on principle to murdering plutocrats like Scarsdale Vibe. Writing about such characters in our own age of terror, one might expect Mr. Pynchon to have given some thought to the rights and wrongs of political violence.

In fact, however, his attitude towards violence is childishly sentimental, and ruthless in a way only possible to a writer whose imagination has never dwelt among actual human beings. Mr. Pynchon’s heroes (the poor, the workers, Anarchists) assassinate and blow up his villains (mine owners, Pinkerton thugs, the bourgeoisie) with no more qualms than the Road Runner has about dropping an anvil on the Coyote. In the novel as in the cartoon, good and evil are unproblematic, death is unreal, and sheer activity takes the place of human motive. The silliness of “Against the Day” about the very subjects where we are most urgently in quest of wisdom proves that, whatever he once was, Thomas Pynchon is no longer the novelist we need.

akirsch@nysun.com