Bertha Muzzy Sinclair or Sinclair-Cowan, (November 15, 1871 - July 23, 1940), best known by her pseudonym B. M. Bower, was an American author who wrote novels, fictional short stories, and screenplays about the American Old West. Her works, featuring cowboys and cows of the Flying U Ranch in Montana, reflected "an interest in ranch life, the use of working cowboys as main characters (even in romantic plots), the occasional appearance of eastern types for the sake of contrast, a sense of western geography as simultaneously harsh and grand, and a good deal of factual attention to such matters as cattle branding and bronc busting." She was married three times: to Clayton Bower in 1890, to Bertrand William Sinclair (also a Western author) in 1905, and to Robert Elsworth Cowan in 1921. However, she chose to publish under the name Bower.Born Bertha Muzzy in Otter Tail County, Minnesota, to Washington Muzzy and Eunice Miner Muzzy, Bower moved with her family to a dryland homestead near Great Falls, Montana, in 1889. That fall, just before her eighteenth birthday, she began teaching school in nearby Milligan Valley. The school was a small, hastily converted log outbuilding, and she taught twelve pupils. Her experiences as a teacher informed the characters of schoolma'ams who appear frequently in her in the writings, notably in The North Wind Do Blow (1937), in which a young, eastern-born schoolma'am teaches her first term in central Montana. After one term as a schoolteacher, Bower returned to her family's homesteadOn December 21, 1890, Bower shocked her family by eloping with her first husband, Clayton J. Bower. Their marriage was unhappy. The newlyweds lived first with the Muzzy family, moving later to Great Falls and then to Big Sandy, Montana, in 1898. Her experiences in Big Sandy gave her intimate knowledge of cowboy life on the open range. Bower gave birth to three children during her marriage to Clayton: Bertha Grace in 1891, Harold Clayton in 1893, and Roy Noel in 1896. Eventually, Clayton moved the family to a lonely hayfield cabin, which Bower nicknamed "Bleak Cabin," about a mile out of Big Sandy. To help with rent, the Bowers accepted a boarder named Bill Sinclair. Sinclair, aged twenty-two, was nine years younger than Bower, but nevertheless a partnership began between them. Bower lent books to Sinclair and tutored him in writing while he helped her understand the finer points of cowpunching and critiqued the Western stories she had begun to write.