The popularity of Hemingway's work depends on its themes of love, war, wilderness and loss, all of which are strongly evident in the body of work. These are recurring themes in American literature, and are quite clearly evident in Hemingway's work. Critic Leslie Fiedler sees the theme he defines as "The Sacred Land"—the American West—extended in Hemingway's work to include mountains in Spain, Switzerland and Africa, and to the streams of Michigan. The American West is given a symbolic nod with the naming of the "Hotel Montana" in The Sun Also Rises and For Whom the Bell Tolls. According to Stoltzfus and Fiedler, in Hemingway's work, nature is a place for rebirth and rest; and it is where the hunter or fisherman might experience a moment of transcendence at the moment they kill their prey. Nature is where men exist without women: men fish; men hunt; men find redemption in nature. Although Hemingway does write about sports, such as fishing, Carlos Baker notes the emphasis is more on the athlete than the sport. At its core, much of Hemingway's work can be viewed in the light of American naturalism, evident in detailed descriptions such as those in "Big Two-Hearted River".
Fiedler believes Hemingway inverts the American literary theme of the evil "Dark Woman" versus the good "Light Woman". The dark woman—Brett Ashley of The Sun Also Rises—is a goddess; the light woman—Margot Macomber of "The Short Happy Life of Francis Macomber"—is a murderess. Robert Scholes admits that early Hemingway stories, such as "A Very Short Story", present "a male character favorably and a female unfavorably". According to Rena Sanderson, early Hemingway critics lauded his male-centric world of masculine pursuits, and the fiction divided women into "castrators or love-slaves". Feminist critics attacked Hemingway as "public enemy number one", although more recent re-evaluations of his work "have given new visibility to Hemingway's female characters (and their strengths) and have revealed his own sensitivity to gender issues, thus casting doubts on the old assumption that his writings were one-sidedly masculine." Nina Baym believes that Brett Ashley and Margot Macomber "are the two outstanding examples of Hemingway's 'bitch women.'"The world breaks everyone and afterward many are strong in the broken places. But those that will not break it kills. It kills the very good and the very gentle and the very brave impartially. If you are none of these you can be sure it will kill you too but there will be no special hurry.
—Ernest Hemingway in A Farewell to Arms
The theme of women and death is evident in stories as early as "Indian Camp". The theme of death permeates Hemingway's work. Young believes the emphasis in "Indian Camp" was not so much on the woman who gives birth or the father who kills himself, but on Nick Adams who witnesses these events as a child, and becomes a "badly scarred and nervous young man". Hemingway sets the events in "Indian Camp" that shape the Adams persona. Young believes "Indian Camp" holds the "master key" to "what its author was up to for some thirty-five years of his writing career". Stoltzfus considers Hemingway's work to be more complex with a representation of the truth inherent in existentialism: if "nothingness" is embraced, then redemption is achieved at the moment of death. Those who face death with dignity and courage live an authentic life. Francis Macomber dies happy because the last hours of his life are authentic; the bullfighter in the corrida represents the pinnacle of a life lived with authenticity. In his paper The Uses of Authenticity: Hemingway and the Literary Field, Timo Müller writes that Hemingway's fiction is successful because the characters live an "authentic life", and the "soldiers, fishers, boxers and backwoodsmen are among the archetypes of authenticity in modern literature".
The theme of emasculation is prevalent in Hemingway's work, most notably in The Sun Also Rises. Emasculation, according to Fiedler, is a result of a generation of wounded soldiers; and of a generation in which women such as Brett gained emancipation. This also applies to the minor character, Frances Clyne, Cohn's girlfriend in the beginning in the book. Her character supports the theme not only because the idea was presented early on in the novel but also the impact she had on Cohn in the start of the book while only appearing a small number of times. Baker believes Hemingway's work emphasizes the "natural" versus the "unnatural". In "Alpine Idyll" the "unnaturalness" of skiing in the high country late spring snow is juxtaposed against the "unnaturalness" of the peasant who allowed his wife's dead body to linger too long in the shed during the winter. The skiers and peasant retreat to the valley to the "natural" spring for redemption.
Susan Beegel has written that some more recent critics—writing through the lens of a more modern social and cultural context several decades after Hemingway's death, and more than half a century after his novels were first published—have characterized the social era portrayed in his fiction as misogynistic and homophobic. In her 1996 essay, "Critical Reception", Beegel analyzed four decades of Hemingway criticism and found that "critics interested in multiculturalism", particularly in the 1980s, simply ignored Hemingway, although some "apologetics" have been written. Typical, according to Beegel, is an analysis of Hemingway's 1926 novel, The Sun Also Rises, in which a critic contended: "Hemingway never lets the reader forget that Cohn is a Jew, not an unattractive character who happens to be a Jew but a character who is unattractive because he is a Jew." Also during the 1980s, according to Beegel, criticism was published that focused on investigating the "horror of homosexuality" and the "racism" typical of the social era portrayed in Hemingway's fiction. In an overall assessment of Hemingway's work Beegel has written: "Throughout his remarkable body of fiction, he tells the truth about human fear, guilt, betrayal, violence, cruelty, drunkenness, hunger, greed, apathy, ecstasy, tenderness, love and lust."