Chapter 1
Steinbeck creates himself as narrator; initially this "character" paints a vivid picture of the Salinas Valley through childhood recollections. He establishes his roots by recalling his father and grandfather. The physical description of the valley is replete with contrasts, as is the book itself. He focuses on the richness of the valley and the dryness of the foothills. Dwelling on natural cycles, he writes of the riverbed full to bursting in the winter and arid in the summer; of years of rainfall and years of drought. He then turns to the Valley's history, the place inhabited by Indians, Spanish and Americans in succession—these peoples were not at one with their surroundings, as they were either indifferent or chose to exercise power over their environment. Chapter 1 defines the symbolic landscape, the setting, of most of the novel.

Chapter 2
Steinbeck's real grandfather, Samuel Hamilton, and his wife, Liza, arrive in the region around 1870 from the north of Ireland, where he was a farmer "neither rich nor poor." They settle in the barren foothills east of King City, for fertile land in the valley is affordable only to men of means. An educated blacksmith, carpenter and woodcarver with a love for poetry and philosophy, he is "scrupulously honest" and "full of inventions and energy." In his business dealings, he shows no talent for making money but is soothing and a great storyteller, "a comical genius." In contrast to his robustness and outgoing nature, Liza is tiny and self-contained, not a woman to show her feelings. Devoutly religious, she holds "small round convictions" and has "a finely developed sense of sin." She bears nine children, four boys and five girls, all delivered by her husband. The Hamiltons scratch out a living on seventeen hundred and sixty acres of hardscrabble land. Although Steinbeck never really knew his grandfather, who died when Steinbeck was 2 years old, this material is based closely on family history. Throughout the novel, the Hamilton stories are true to what actually happened, with dates shifted slightly. Chapter 3
Having introduced the Hamiltons, the novel now introduces the Trasks by shifting to "a farm on the outskirts of a little town not far from a big town in Connecticut." Adam Trask is born six months after his father's induction into the Union Army in 1862 during the Civil War. Cyrus Trask, wild and fun-loving by nature, returns with a wooden leg and "the clap" (gonorrhea) soon after Adam's birth. Mrs. Trask, a deeply religious woman, contracts the disease and commits suicide by drowning, thinking it God's punishment for her "nocturnal philandering." Cyrus remarries a consumptive young woman, Alice, mother of Charles, less than a year younger than Adam. Their father, a liar about his exploits in the war, imposes a strict military regimen on the boys. Charles, violent and cold-blooded, brutally beats and nearly murders Adam, who is sensitive and retiring. Charles is jealous of his father's intimacy with Adam. He suffers from rejection; he doesn't think that his father loves him. Charles had given his father a pen-knife as a birthday present, which Cyrus had barely acknowledged. Cyrus, a figure of authority, a god to the boys, favored Adam's present, a puppy. Here is the first reference to the Cain and Abel story, which, on a social level, also serves to interpret war itself (remember that the book spans the period from the Civil War to World War I). As Cyrus tells Adam: "We take a soldier and put murder in his hands and say to him, 'Use it well, use it wisely.' We put no checks on him. Go out and kill as many of a certain kind or classification of your brothers as you can." Chapter 4
Cyrus, armed with a shotgun, goes in search of Charles, presumably to kill him for his violent abuse of Adam, but doesn't find him. Charles hides out for two weeks before returning home, Cyrus's anger having subsided. Adam, who is convalescing, is forced to enlist in the army—as a private in the cavalry—by his father, who wants to make a man of him. Over the next five years, Adam is a pacifist soldier during his five years of Indian fighting. ("When he fired his carbine to miss he was committing treason against his unit, and he didn't care. The notion of nonviolence was building in him until it became a prejudice. ... To inflict hurt on anything for any purpose became inimical to him.") Charles and Adam exchange letters, becoming closer than either one could have imagined. By now, because of his expertise in military matters acquired mostly from reading and his writings on the subject, Cyrus has become a famous military advisor in the G.A.R. (Grand Army of the Republic). The chapter concludes with a letter from Charles to Adam that Steinbeck insisted was key to any proper understanding of East of Eden.

Chapter 5
We are back in the Salinas Valley, where the Hamiltons are fleshed out. ("On the ranch the little Hamiltons began to grow up, and every year there was a new one.") George, tall and handsome, is polite and gentle, neat and considerate. Will is "dumpy and stolid," a hard worker who is conservative in all matters. Tom, the third son, is bold and inventive and most like his father. "He was born in fury and lived in lightning...as he was capable of giant joy, so did he harbor huge sorrow." Joe, the youngest son, is spacey and helpless, beloved and protected from hard work by the family. In addition to four boys, there are five girls. Una is, a thoughtful, studious, dark girl;" Lizzie (named after her mother) who, unlike other Hamiltons had "a capacity for bitterness and hatred," "married young and went away and thereafter was seen only at funerals;" Dessie, "whose laughter was so constant that everyone was glad to be there because it was more fun to be with Dessie than with anyone else;" Olive, John Steinbeck's mother; and Mollie, "who was a little beauty with lovely blond hair and violet eyes." Chapter 6
His father having moved to Washington, Charles lives a lonely existence on the farm in Connecticut, in the gloomy and decaying house. He is restless and devotes all his energy to improving the land. "At least every two weeks," he consorts with prostitutes at the Inn in town. "He missed his brother more than he missed his father and mother," long dead. "In the third year of his aloneness," he suffers an accident that leaves a scar, a mark, between his eyebrows (i.e., the mark of Cain). Adam is discharged from the army in 1885. He, too, feels "a crippling loneliness" and, on his way home, wanders from Chicago to Buffalo to Niagara Falls. One night after drinking in a smoky little bar, he returns to his boarding house and feels in his bones that he cannot go back home to Connecticut. He returns to Chicago to re-enlist, only to be summoned to Washington, where his father is an unrecognizable, prominent man of influence with the Secretary of War. Cyrus, who is also "lonely and alone" tries to impress his son by offering him admission to West Point. Adam defies him, preferring to go his own way and return to his regiment. This is the last time they will see each other. Meantime, Charles has been anxiously awaiting Adam's return and learns of his re-enlistment from Cyrus. A year later Charles and Adam write to each other but have grown far apart. Charles sinks into a funk and begins "to keep one slovenly woman after another," spending "most of his money and all his energy on the farm." Chapter 7
After his second five-year stint in the army, in late 1890, Adam is discharged in San Francisco and writes Charles to say: "'This time I'm coming home,' and that was the last Charles heard of him for over three years." Adam becomes a hobo, a tramp, wandering by train and on foot as far as Florida. Near Tallahassee he is arrested for vagrancy and sentenced on two occasions, for nearly a year, to a road gang. He runs away and ends up near Valdosta, Georgia, where at night he steals food and clothing to survive. In February 1894, Charles receives a letter from his father's attorneys informing him that Cyrus has died and had an impressive funeral with dignitaries in attendance. Charles and Adam inherit more than one hundred thousand dollars, setting Charles to wonder how his father came about the money. A few weeks later he gets a telegram from Adam asking him to send one hundred dollars. The question that the recipient must answer is: "'What did you give your father on his birthday just before you went into the army?'" Adam returns and he and Charles dance around the issue of whether Cyrus had been dishonest in amassing their inheritance. Charles worries for Cyrus's reputation; he confesses that he loved his father. Adam says that he did not and suggests that they might use the money to move to California.

Chapter 8
We are introduced to one of the great villains in all of American literature, Cathy Ames, a character who is pivotal to the unfolding of the novel. From the outset, the narrator calls her a moral monster by nature. While she seems to possess childlike innocence (she is "dainty and very sweet and her voice was low"), and is angelically pretty, he describes her as serpent-like: "her ears were very little, without lobes, and they pressed so close to her head that even with her hair combed up they made no silhouette. They were thin flaps sealed against her head." She is a highly gifted, natural-born liar who knows how to manipulate weaknesses in others. As a child in a small town in Massachusetts, she "learned when she was very young that sexuality with all its attendant yearnings and pains, jealousies and taboos, is the most disturbing impulse humans have." At age ten she is discovered, by her mother, with her hands tied and naked to the waist in a barn with two fourteen-year-old boys. For this, the boys are sternly punished. At fourteen, she so seduces her Latin teacher that he shoots the top of his head off with a shotgun. At sixteen, she becomes cold to her parents and declares that she will no longer be going to school. She kills them in a craftily staged fire in which robbery is suspected. The townspeople frantically search for her missing body. Chapter 9
Having run away, Cathy "Amesbury" seeks out Mr. Edwards of Boston—a "cold-blooded" whoremaster and religious family man—and offers her services. He finds her "far too pretty for his business" and is at first suspicious of her. Even though "he never mixed his professional life with his private pleasures," he is seduced by her and falls hopelessly in love. He "fell right into the oldest conviction in the world—that the girl you are in love with can't possibly be anything but true and honest." Cathy lies to him, saying that her father is dead, having left their estate in chaos. She needs to make money, she claims, to prevent the bank from foreclosing on her family's farm for her mother's sake. Mr. Edwards tries to secure Cathy's love and loyalty by setting her up in a house and lavishing her with presents and money. To her, he is simply a business proposition and she knows how to work him. She frequently makes herself unavailable and suggests to him that he is sexually unsatisfying. He tries to ply her with champagne, not knowing that when Cathy drinks she becomes cold and verbally abusive. He falls into miserable jealousy and spies on her. One day he reads "an old newspaper account of a fire from a small town weekly." He becomes enraged and violent, takes her to the outskirts of a little town in Connecticut—supposedly on business—and gives her the beating of her life, leaving her for dead.

Chapter 10
Charles and Adam go to Washington to collect their inheritance, Cyrus's money. Back at the farm in Connecticut they quarrel as brothers: Charles is an early riser always ready to work; Adam is a lay-a-bout. After one squabble, Adam disappears for eight months before returning home. The brothers continue to argue about Charles's rootedness at the farm and Adam's restlessness. Adam keeps bringing California up as a place to settle, and laments their not having wives and children. He leaves the farm and goes abroad to Rio de Janeiro, Brazil, and Buenos Aires, Argentina, sending postcards to Charles. Adam comes back and the brothers settle into the old routine: "For a while they reviewed old times, for a while they recounted the times when they were apart, and finally they relapsed into the long ugly silences, the hours of speechless work, the guarded courtesy, the flashes of anger." Charles mentions that Adam never paid him back the hundred dollars he wired to Valdosta, Georgia, and Adam relates his time on the road gang, resulting in Charles's admiration and a deeper bond between the brothers.

Chapter 11
As Charles and Adam talk about what to do with their new-found money, a battered and bedraggled Cathy Ames makes her way to the Trask farm. Charles is against taking her in, fearing what the townspeople might think. No good can come from this woman, he predicts. But Adam is all for being a Good Samaritan, and sends the unwilling Charles to fetch a doctor. As Cathy convalesces, Adam devotedly watches over her. He is happier than he has ever been. She claims to be suffering from amnesia when the town's sympathetic sheriff comes to investigate. Charles is deeply suspicious of Cathy and—one afternoon when Adam has gone to get medicine—tells her that he has heard her talking in her sleep, and threatens to expose her and throw her out soon. Cathy is frightened, but sees in Charles the same darkness that is in her. She sets about regaining control of the situation by manipulating Adam. When Adam returns, she—sweet and helpless—tells him of Charles's threat, and asks him to trust her. In a quarrel with his brother, Charles denounces Cathy as "a two-bit whore." But Adam, who can see only goodness in Cathy, marries her. One night as Adam prepares to watch over his frail new bride, Cathy spikes his tea with her sleeping medicine and climbs into bed with Charles.