APL has been making critical contributions to critical challenges for nearly 70 years across a broad range of technical areas and systems. The development of complex, adaptive systems that often must perform autonomously in extreme environments is a true test of all of the underlying research, architectures, processes, and testing that occur with systems engineering. Our accomplishments are based on our application of systems engineering principles and practices, tightly coupled with broad and deep domain knowledge in the operational environments of these systems. Success requires pervasive use of innovative systems thinking coupled with in-depth “hands-on” experience and understanding of the technologies within which the system or system-of-systems must operate. The systems engineer must exercise strong interdisciplinary leadership and collaborate with government institutions, private industry, professional societies, and academia throughout the world to bring the best expertise and resources to bear on the world’s challenging problems.