It was introduced for the awards' 1988 iteration, replacing the earlier category of Best Historical Novel.
John Mort explains the distinction in his book Read the High Country: "WWA defines Westerns... in market terms.
A Western novel is a 'traditional' tale of revenge, rival cattlemen at war, or settlers fighting Indians.
Owen Wister's The Virginian is a famous example, as well as Louis L'Amour's Hondo.
"[2] During 2000, the official Spurs Award website defined both categories as "book-length novels... dependent in whole or in part on settings, characters, conditions, or customs indigenous to the American West or early frontier," the distinction being that Best Western Novel was for works "90,000 words or less" while Best Novel of the West was for works "90,000 words or more.