The Sun Also Rises is a modernist novel. Hemingway's modernist experimentation is evident in his use of nontraditional expository narration through his trademark clipped sentences. This style ultimately follows his “iceberg theory” of writing, in which minimalist phrases and remarks—both in narration and dialogue—leave much unsaid.
The Sun Also Rises is also a roman à clef, or literally a "novel with a key"—a book written largely as non-fiction but treated (through some obfuscation of personal details, use of fictitious names, or other fictionalizing elements) as a fictional novel. In its original form in 17th-century French literature, the author of a roman à clef would arm the reader directly or indirectly with some sort of “key,” which could be consulted alongside the text to lead the reader to the true story lying underneath.
Although Hemingway includes no explicit “key,” The Sun Also Rises nonetheless engages with his circle of friends, life, and travels in Paris and Spain in the 1920s. The character of Jake is based on Hemingway himself, who worked as a foreign correspondent for the Torno Star throughout the 1920s and went to the Festival of San Fermín in Pamplona in 1923, 1924, and 1925 with different groups of expatriate friends. In 1924 and 1925, Hemingway also stayed in Burguete – Auritz to fish along the Irati river (though there are, of course, also a number of characteristics that distinguish Jake from Hemingway himself).