Taking up its position astride the Peking-Mukden [Beijing-Shenyang] railway beginning in January, 1912, the United States Fifteenth Infantry Regiment was engaged in protecting American interests in China. The 1000 man force was especially challenged during the 1920s, those tumultuous years when warlords struggled to gain ascendancy in the Chinese Republic. Although Chiang Kai-shek established a measure of control in China by 1928, the regiment remained in China - partially to counter Japan's increasingly aggressive actions - despite considerable misgivings within and outside of the United States Army as to the feasibility, desirability, and ethical appropriateness of the policy retaining it there. The success of the Japanese in conquering much of eastern China finally compelled Washington to withdraw the regiment on March 2, 1938. This work recounts and assesses some aspects of the involvement and service of the Fifteenth Infantry Regiment during its fateful quarter of a century in the Orient between the World Wars. Also detailed is the Army's service in those years in general. Many insights are provided regarding the self-perceptions of a key generation of U.S. military personnel deployed there.