Due to their nearly hopeless situation, and in part because they are trapped in the Dust Bowl, the Joads set out for California on the "mother road", along with thousands of other "Okies" seeking jobs, land, dignity, and a future.

The Grapes of Wrath is frequently read in American high school and college literature classes due to its historical context and enduring legacy.

Disconcerted and confused, Tom and Casy meet an old neighbor, Muley Graves, who says the family is at Uncle John Joad's home nearby.

At the first migrant Hooverville camp the Joads stop at, Casy is arrested for knocking down a deputy sheriff who is about to shoot a fleeing worker for alerting others that the labor recruiter, travelling with the officer, will not pay the wages he is promising.

The Joads quietly leave the orchard to work at a cotton farm where Tom risks being arrested, and possibly lynched, for the homicide.

Scholars have regularly inspected other characters and plot points within the novel, including Ma Joad, Rose of Sharon, her stillborn child, and Uncle John.

In an article first published in 2009, Ken Eckert even compared the migrants' movement west as a reversed version of the slaves' escape from Egypt in Exodus.

[7] To expand upon previous remarks in a journal, Leonard A. Slade lays out the chapters and how they represent each part of the slaves escaping from Egypt.

The Grapes of Wrath developed from The Harvest Gypsies, a series of seven articles that ran in the San Francisco News, from October 5 to 12, 1936.

While she collected personal stories about the lives of the displaced migrants for a novel she was developing, her supervisor, Tom Collins, shared her reports with Steinbeck, who at the time was working for the San Francisco News.

In mid-January 1939, three months before the publication of The Grapes of Wrath, Steinbeck wrote a long letter to Pascal Covici, his editor at Viking Press.

And so he concluded with a statement that might serve as preface in and of itself: "Throughout I've tried to make the reader participate in the actuality, what he takes from it will be scaled on his own depth and shallowness.

"[12] While writing the novel at his home, 16250 Greenwood Lane, in what is now Monte Sereno, California, Steinbeck had unusual difficulty devising a title.

The title is a reference to lyrics from "The Battle Hymn of the Republic", by Julia Ward Howe (emphasis added): Mine eyes have seen the glory of the coming of the Lord: He is trampling out the vintage where the grapes of wrath are stored; He hath loosed the fateful lightning of His terrible swift sword: His truth is marching on.

These lyrics refer, in turn, to the biblical passage Revelation 14:19–20, an apocalyptic appeal to divine justice and deliverance from oppression in the final judgment.

In the souls of the people the grapes of wrath are filling and growing heavy, growing heavy for the vintage.The image invoked by the title serves as a crucial symbol in the development of both the plot and the novel's greater thematic concerns: from the terrible winepress of Dust Bowl oppression will come terrible wrath but also the deliverance of workers through their cooperation.

When preparing to write the novel, Steinbeck wrote: "I want to put a tag of shame on the greedy bastards who are responsible for this [the Great Depression and its effects]."

[14] Steinbeck scholar John Timmerman sums up the book's influence: "The Grapes of Wrath may well be the most thoroughly discussed novel – in criticism, reviews, and college classrooms – of 20th century American literature.

[4] The book was noted for Steinbeck's passionate depiction of the plight of the poor, and many of his contemporaries attacked his social and political views.

[5] In 1999, French newspaper Le Monde of Paris ranked The Grapes of Wrath as seventh on its list of the 100 best books of the 20th century.

[22] The Grapes of Wrath has faced a great amount of controversy since publication, including book bans and other challenges on a variety of political and religious grounds in the United States and other countries.

Among other scenes and themes repeated in both books: the villainy of banks, corporations, and company stores that charge exorbitant prices; the rejection of religion and the embrace of music as a means of preserving hope; descriptions of the fecundity of nature and agriculture, and the contrast with the impoverishment of the migrants; and the disparity between those willing to extend assistance to the migrants and others who view "Okies" as subhuman.

"[28] Writing in Broad Street (magazine), Carla Dominguez described Babb as "devastated and bitter" that Random House cancelled publication of her own novel after The Grapes of Wrath was released in 1939.

"[29] The book was quickly made into a famed 1940 Hollywood movie of the same name directed by John Ford and starring Henry Fonda as Tom Joad.

[32][33] The Japanese animated series Bungou Stray Dogs portrays a character based on Steinbeck whose superpower is named "The Grapes of Wrath".

Woody Guthrie's two-part song—"Tom Joad – Parts 1 & 2" – from the album Dust Bowl Ballads (1940), explores the protagonist's life after being paroled from prison.

[34] The 1981 song "Here Comes that Rainbow Again", by Kris Kristofferson, is based on the scene in the roadside diner where a man buys a loaf of bread and two candy sticks for his sons.

[38][better source needed][failed verification] The song "Dust Bowl Dance", on the Mumford & Sons album Sigh No More (2009), is based on the novel.

The Pink Floyd song "Sorrow", written by front-man David Gilmour and included on the band's album A Momentary Lapse of Reason, is thematically derived from/based on the novel.

The song "Grapes Of Wrath" by Weezer, written by Rivers Cuomo from their album "OK Human" (2021), takes its title directly from the novel.