Abstract The Lieber Code succinctly and comprehensively clarified and summarized the customary laws of armed conflict through a practical humanitarian lens. Of particular contemporary relevance is how the Lieber Code addresses prisoners of war (POWs). Though some of the thirty-eight articles in the Code on POWs are undoubtedly anachronistic, the provisions on categorization and treatment continue to inform the law of armed conflict. His contribution to the development of the law of armed conflict was particularly significant in this regard, as it was the first instrument to contain a clear articulation of which persons were entitled to protection as POWs and which were not. Additionally, he addressed not only the treatment of POWs, but also confronted the horrendous discrimination and maltreatment of Black soldiers by confirming the law of nations knows of no distinction of color. Finally, the Lieber Code confronted the thorny issues of paroles, prisoner exchanges, and reprisals under the law of armed conflict. Of course, some provisions of the Code did not survive the test of time. But, for those that did, commanders, legal advisers, policymakers, and scholars will continue to look to them as they shape the law of armed conflict into the twenty-first century.