While he is still a peasant boy in Lithuania, Jurgis Rudkus falls in love with a gentle girl named Ona. When Ona’s father dies, Jurgis, planning to marry her as soon as he has enough money, comes to America with her family. Besides the young lovers, the emigrant party is composed of Dede Antanas, Jurgis’s father; Elzbieta, Ona’s stepmother; Jonas, Elzbieta’s brother; Marija, Ona’s orphan cousin; and Elzbieta’s six children. By the time the family arrives in Chicago, they have very little money. Jonas, Marija, and Jurgis at once get work in the stockyards. Dede Antanas tries to find work, but he is too old.

They decide that it will be cheaper to buy a house on installments than to rent. A crooked agent sells them a ramshackle house with a fresh coat of paint that he describes to his ignorant customers as new. Jurgis finds his job exhausting, but he thinks himself lucky to be making forty-five dollars a month. At last, Dede Antanas also finds work at the plant, but he has to give part of his wages to the foreman in order to secure his job.

Jurgis and Ona save enough money for their wedding feast and are married. Then the family finds that they need more money. Elzbieta lies about the age of her oldest son, Stanislovas, and he, too, gets a job at the plant. Ona is already working. Dede Antanas works in a moist, cold room, where he develops consumption. When he dies, the family has scarcely enough money to bury him. Winter comes, and everyone suffers in the flimsy house. When Marija loses her job, the family income diminishes. Jurgis joins a union and becomes an active member. He goes to night school to learn to read and to speak English.

At last, summer comes with its hordes of flies and oppressive heat. Marija finds work as a beef trimmer, but at that job the danger of blood poisoning is very great. Ona has a baby, a fine boy, whom they call Antanas after his grandfather. Winter comes again, and Jurgis pulls a tendon in his ankle while attempting to avoid a rampaging steer at the plant. Compelled to stay at home for months, he becomes moody. Two more of Elzbieta’s children leave school to sell papers. When Jurgis is well enough to look for work again, he can find none, because he is no longer the strong man he was. Finally, he gets a job in a fertilizer plant, a last resort, for men last only a few years at that work.

One of Elzbieta’s daughters is now old enough to care for the rest of the children, and Elzbieta also goes to work. Jurgis begins to drink. Ona, pregnant again, develops a consumptive cough and is often seized with spells of hysteria. Hoping to save her job, she allows herself to be seduced by her boss, Connor. When Jurgis learns what she did, he attacks Connor and is sentenced to thirty days in jail. Having time to think in jail, Jurgis sees how unjustly he is treated by society. No longer will he try to be kind, except to his own family. From now on, he will recognize society as an enemy rather than as a friend.

After he serves his sentence, Jurgis goes to look for his family. He finds that they lost the house because they could not meet the payments and moved. He finds them at last in a rooming house. Ona is in labor with her second child, and Jurgis frantically searches for a midwife. By the time he finds one, Ona and the child are past saving. Now he has only little Antanas to live for. He tries to find work. Blacklisted in the stockyards for his attack on Connor, he finally finds a job in a harvesting machine factory. Soon after, he is discharged when his department closes down for a lack of orders.

Next he goes to work in the steel mills. In order to save money, he moves near the mills and comes home only on weekends. One weekend he comes home to find that Antanas drowned in the street in front of the house. In order to flee his inner demons, his remorse, and his grief, he hops a freight train and rides away from Chicago. He becomes one of the thousands of hobos and workers; his old strength comes back in healthful, rural surroundings.

In the fall, Jurgis returns to Chicago. He gets a job digging tunnels under the streets. Then a shoulder injury makes him spend weeks in a hospital. Discharged with his arm still in a sling, he becomes a beggar. By luck he obtains a hundred-dollar bill from a drunken son of a packing owner. When he goes to a saloon to get it changed, however, the barkeeper tries to cheat him out of his money. In a rage, Jurgis attacks the man. He is arrested and sent to jail again. There he becomes acquainted with a dapper safecracker, Jack Duane, whom he met during his last incarceration. After their release, Jurgis joins Duane in several muggings and becomes acquainted with Chicago’s underworld. At last, he is making money.

Jurgis becomes a political worker. About that time, the packing plant workers begin to demand more rights through their unions. When packinghouse operators will not listen to union demands, there is a general strike. Jurgis goes to work in the plant as a scab and is given a managerial position. One night, however, he meets Connor and attacks him again. After getting out on bond and learning that Connor is well connected, Jurgis flees from the district to avoid a penitentiary sentence. On the verge of starvation, he finds Marija working as a prostitute. Jurgis is ashamed to think how low he and Marija fell since they came to Chicago.

Jurgis leaves, despondent, but he happens upon a socialist meeting. He experiences something like a religious transformation. At last, he knows how the workers can find self-respect. He finds a job in a hotel where the manager is a socialist. It is the beginning of a new life for Jurgis, the rebirth of hope and faith.

The abuses in the meatpacking industry were known before the publication of The Jungle. In the 1898 intervention in Cuba, some three thousand American soldiers died from eating canned beef, and (soon to be President) Theodore Roosevelt himself testified against the Beef Trust. The Hearst newspapers brought about a Senate investigation, and there were several muckraking exposés, but little changed until Sinclair’s fateful trip to Chicago to observe immigrant workers at work. Although he had little interest in them as immigrants, Sinclair’s descriptions of their customs, mentality, and behavior are some of the best in American letters. Similarly, he had little interest as such in attacking the beef industry. He dedicated the novel “To the Workingmen of America,” underscoring his goal of improving their overall conditions rather than exposing the filth prevailing in the country’s slaughterhouses. After the sensational success of The Jungle—in London, Winston Churchill penned a glowing review article—Sinclair avowed that he aimed at the public’s heart and accidentally hit it in the stomach.

Between the opening chapter of an ethnic wedding and the closing scenes of a political rally, the novel traces more than two years in the life of a newly arrived Lithuanian immigrant family. Lured by the advertising blitz that promised them the American Dream, they instead suffer almost unbearable exploitations and deprivations at the hands of unscrupulous lawyers, shysters, judges, police, and Packingtown bosses. Working their hands to the bone, they gradually lose their house, jobs, livelihood, and dignity to layoffs, malnutrition, industrial accidents, prostitution, and for some, even death.

Most of the story centers on the newlywed Jurgis. At the outset, he is healthy, optimistic, and fired up with confidence in his ability to earn a living and prove a model worker. Halfway through, having lost his job, health, family, and hope, in a poignant epiphany he sees himself as a squealing hog led to slaughter, one among thousands fed into the industrial machine on the conveyer belt of systematic exploitation. Toward the end, having gotten out of the Midwest and traveled as a hobo throughout the land like a character out of a Jack London story, Jurgis returns north to discover the precepts of socialism and the brotherhood of working-class organizers. It is at this point that Sinclair’s hard-hitting and starkly mesmerizing book loses much of its narrative momentum, getting bogged down in a series of ill-masked exhortations of socialism.

Although Sinclair had to tone down the book version in a number of ways, he preserved the material relating to the unhygienic and corrupt practices on the slaughterhouse floor, much as the telling alliteration of the meatpacking moguls (Anderson, Smith, and Morton stand for the real-life meatpacking firms of Armour, Swift, and Morris). Once released, the novel became widely popular; a nationwide scandal erupted overnight, so much so that a popular song changed into: “Mary had a little lamb/ And when she saw it sicken/ She shipped it off to Packingtown/ And now it’s labeled chicken.” Riding the wave of disgust and media-fanned protests, Sinclair ended up being invited to the White House, where the groundwork was laid for the 1906 Pure Food and Drug Act and Meat Inspection Act. By the early twenty-first century, The Jungle had almost eight hundred different editions in some fifty languages, cementing Sinclair’s reputation as one of the most distinguished literary figures of the early twentieth century.

Sinclair embraced socialism in 1903 and saw The Jungle as a platform to explore capitalism's exploitation of laborers. The story centers on Jurgis Rudkus, a Lithuanian immigrant, as he grapples with a brutal environment where only the merciless thrive. The novel begins with Jurgis's vesilija, or Lithuanian wedding feast—a ceremony symbolizing personal hope and the reaffirmation of traditional values. Jurgis faces challenges from the harsh conditions of the Chicago stockyards, which symbolize a society driven by capitalist values. Sinclair presents a political alternative and a remedy for capitalist abuses by depicting Jurgis's eventual shift to socialism. Although Sinclair was not entirely pleased with the mix of rhetorical strategies he used in The Jungle, his vivid portrayal of egregious industrial practices quickly drew public attention to the novel and spurred social reform.