Innovation is a key enabling concept in the 2018 National Defense Strategy. Not only does the US military need to continue to maintain effectiveness in military operations, but in the face of a new competitive environment, and the increasing importance of commercial technology, the US will need to practice innovation to maintain a military edge and meet national security goals. The critical role of innovation is repeated throughout the NDS. But what can the US do to pursue effective innovation? And what is innovation anyway? We examine innovation through consideration of specific military examplesboth historical and contemporaryas well as examining academic literature and past CNA products addressing innovation. After developing a functional definition of innovation, we provide best practices and principles that DOD can apply in order to put innovation into practice.