This chapter explores to sketch how the US system of defense planning has evolved over the half-century, especially with regard to balancing needs against resource limits, and in developing "human capital". The forward planning system used by the US Department of Defense originates from research and reflection at RAND in the 1950s. There should be no doubt that Planning, Programming, and Budgeting System (PPBS) improved the process of deciding what Department of Defense needs. Perhaps the best compliment to the contemporary model of PPBS was paid by the recent Secretary of the Department of Homeland Security. Secretary Johnson adopted that model, with little change, as his instrument for pulling together the disparate elements of his Department into a more coherent and focused whole. "Human capital"—people, their skills and esprit—lie at the heart of any successful military endeavor. Despite the labor-intensive nature of military matters, human capital issues rarely figure in defense planning debates, outside the personnel management domain itself.