The most famous and revealing scenes in Victor Hugo’s Les Misérables get underway fairly late in the novel—on page 1,280 in the Pléiade edition—at the moment when the physically powerful Jean Valjean pries loose an iron-bar sewer grill in a Paris street and prepares to escape into the underground tunnels, carrying on his back the half-dead body of young Marius, the barricade fighter. It is 1832, a year of insurrections. Marius has been battling against the National Guard at Les Halles. The republican rebels have gone down to defeat; the monarchy will stay in power; the guardsmen have broken into the tavern that serves as rebel headquarters; the massacre is about to begin. And Jean Valjean—who is present at the barricade only because he has discovered that his adopted daughter, Cosette, is in love with young Marius, and Marius has decided to sacrifice his life to the doomed revolution, and Jean Valjean, who detests the young man, will do anything for his daughter and therefore is determined to rescue the barricade fighter from his chosen martyrdom—what a plot!—Jean Valjean, steely ex-con, cool under fire, disdainful of authority, bitter, self-reliant, climbs downward with the unconscious young man into the fetid sewer beneath the street.

Jean Valjean pulls the grill back into place above his head. And as he goes creeping through the tunnel, we readers ought to be able to detect amid the gloom a peculiar propulsive energy in Hugo’s book, the mysterious subterranean power that, over the last century and a half, has somehow allowed the gigantic, sprawling text to assume one new shape after another: a theater play in the 1860s, a series of parodies mocking the novel from the same era, silent movies and talkies in the twentieth century (Fredric March and Charles Laughton, among others), a TV mini-series (John Malkovich and Gérard Depardieu), a musical-theater play in France in the 1980s, which evolved into a British production, which ran on Broadway as Les Mis and has been seen, or so it is claimed, by sixty million people, which has now emerged as a teary-eyed movie-opera called Les Misérables, the soundtrack to which has reached number one on the Billboard chart, and which will doubtless give way, soon enough, to still odder, weepier presentations. Les Misérables is many things, but never has it been dead. It respires. It procreates. And there, in the viscous murk of the pages devoted to sewage and tunnels, you can glimpse, bubbling in the mud, a few telling signs of the procreative power at work.

At each of the transition points in the giant book, when the story is about to turn a corner, Hugo interrupts his recitation to launch into long-winded disquisitions on historical and social-scientific themes. In this instance, when the sewer grill clangs shut, he produces a dossier on sewage called “The Intestines of the Leviathan,” with Paris identified as the Leviathan and the sewers as its intestines. The problem of mass poverty, or la misère, has been the novel’s insistent theme from the title onward. By this point in the book Hugo has already made clear at preposterous length that he advocates the grandest of social reforms, beginning with a reform of the human heart. He has shuddered in horror at medieval superstitions; has abominated the police; has throbbed with sympathy for the downtrodden.

Les Misérables is many things, but never has it been dead.

Here and there he has made the case for specific ameliorative policies. Compulsory and free primary education: “the right to the alphabet.” Amnesty and compassion for men such as Jean Valjean whose hardships have driven them to theft, and for women such as Fantine whose hardships have driven them to prostitution. Against capital punishment. Against convents and monasteries: “Who says convent, says swamp.” Hugo has never gotten around to explaining, though, how any of these changes of heart or of policy will do much to alleviate the deeper problem. Higher wages: a good idea. Where will the money come from? No explanation. I do not mean to suggest that, as you go floating along the sundry streams that make up Les Misérables, the lack of wonky specificity will nag at your reading pleasure. In the years since 1862, when the book came out, not a single person has rummaged its pages in hope of discovering a ten-point program.

Still, Hugo himself evidently felt the lack, and in the chapter on the Leviathan and its intestines he presents at last a detailed and practical-sounding proposal. He explains that, under Napoleon, the state undertook a public-works project to modernize the medieval sewage tunnels and cesspools, with admirable results. But progress cries out for more. The sewers, as of 1862, release their wastes into the Seine and the sea. Hugo proposes that, instead, a “double tubular apparatus” be constructed that, instead of polluting the waters, will recycle human manure into the farmlands. Parisian guano will raise the agricultural yield. The tubular apparatus will recycle the pristine waters of the countryside back into the city, and the entire setup will attenuate the problem of poverty—this, together with a new economic policy. “Add the suppression of parasites, and it will be solved.” The splendor of Paris will double.