Here are some of his notable works:
Cowboy Series:
* The Lonesome Trail (1909)
* The Range Dwellers (1910)
* Chip of the Flying U (1911)
* The Flying U Ranch (1913)
* The Trail of the Lonesome Pine (1915)
* The Shadows of the Purple (1916)
* The Lost Wagon Train (1917)
* The Phantom Herd (1919)
* The Desert Trail (1920)
* The Happy Family (1921)
* The Hidden Trail (1922)
* The Cowboy's Confession (1923)
* The Pride of the Range (1924)
* The Sagebrusher (1925)
* The Flying "U" Ranch (1927)
Other Novels:
* The Lure of the Dim Trails (1908)
* The Unseen Hand (1912)
* The Valley of the Giants (1914)
* The Way of the West (1917)
* The Plunderer (1918)
* The Man from Bar-L (1920)
* The Whispering Canyon (1921)
* The Outlaw Trail (1922)
* The Man on the Box (1923)
* The Bluegrass Breed (1924)
* The Trail of the Black Cat (1925)
* The White Range (1926)
* The Trail to Yesterday (1928)
* The Last Frontier (1930)
* The Trail to San Antone (1932)
* The Painted Stallion (1933)
* The Wind in the Saddle (1935)
* The Trail of the Tumbling T (1937)
* The Singing Guns (1940)
Short Story Collections:
* The Short Stories of B.M. Bower (1927)
* The Best Western Stories of B.M. Bower (1935)
Northrop's Western stories are known for their action, romance, and colorful characters. He is considered one of the most important authors of the Western genre.