On publication, New York Times reviewer Fred T. March compared it to the "genial gusto" of the "picaresque" Tortilla Flat. He commented that "You would never know that In Dubious Battle was by the same John Steinbeck if the publishers did not tell you so." He called it "courageous and desperately honest," "the best labor and strike novel to come out of our contemporary economic and social unrest," and "such a novel as Sinclair Lewis at his best might have done had he gone on with his projected labor novel..."
In 1943, with Steinbeck now famous, Carlos Baker "revalued" the novel. He opened by saying "Among Steinbeck's best novels, the least known is probably In Dubious Battle." Steinbeck, he said, "is supremely interested in what happens to men's minds and hearts when they function, not as responsible, self-governing individuals, but as members of a group.... Biologists have a word for this very important problem; the call it bionomics, or ecology." He said that "Steinbeck's bionomic interest is visible in all that he has done, from Tortilla Flat, in the middle Thirties, through his semi-biological Sea of Cortez, to his latest communiqués as a war correspondent in England." He characterized In Dubious Battle as "an attempt to study a typical mid-depression strike in bionomic terms."
In 1958, critic Alfred Kazin referred to In Dubious Battle and The Grapes of Wrath as "his most powerful books," contrasting them with Cannery Row and The Wayward Bus. President Barack Obama told the New York Times that it was his favorite book by Steinbeck.
The novel likely recounts a fruit worker strike that occurred in Tulare County, California.