The main focus of this monograph is to synthesize the top research on leadership and leader development and to highlight the needs for developing individuals committed to careers of service across the public, private, and nonprofit sectors. The foundation for the research is based on ideas drawn from leadership and management literature, government doctrine and reports, think tank studies, and case studies. The Army has long sought to be innovative in its leader development. Most recently, the Army’s Human Development White Paper supports TRADOC Pamphlet 5250301, The U.S. Army Operating Concept, “Win in a Complex World” document (2014), by emphasizing the Army’s desire to become the nation’s leader in “human development.” In short, the Army Operating Concept requires that emerging leaders must understand the political-social-military environmental context, the defense-diplomatic-development (the 3-Ds) policies of the U.S. Government, and their roles as emerging leaders and followers in a variety of operational settings. Collaboration, not just within the Army, but across government agencies will be crucial to success in this complex operating environment.