In this research study, former Defense Department consultant George Refuto traces the technological evolution of USAF long-range strategic nuclear bomber aircraft during and after the Cold War, as well as the development of their missions and utilization of US nuclear bombers in 21st century regional and global military threat scenarios. Five distinct periods are covered in this study: World War I (1914-1918), the Interwar Period (1919-1939), World War II (1939-1945), the Cold War (1946-1991), and the Post-Cold War Period (1991-present), with an emphasis on the latter two. In his writing, Refuto focuses on developing a model that encompasses bombing and air defense for each period, and showing how concepts, technologies, and implementations of strategic bombing have changed and influenced the current level of development of the USAF strategic nuclear bomber force and doctrine, and what is projected for the future.