Book excerpt: The book provides a much-needed review of the “Turning Point” in the evolution of airborne threat warning systems from analog to digital beginning in the early 1970s and the combat conditions of the Vietnam War that brought about the evolution. The military operational requirement for reprogrammability of threat characteristics is described and detailed. Illustrations of several types of radar warning receiver (RWR) processors are shown. Basic software structures and functions are reviewed and top-level flow charts and diagrams of critical algorithms and circuits of the original systems are discussed. The ‘electro-political’ environment is treated also in the retelling of the origins of the developmental impetus, as well as the technical approach and resource applications that resulted in the new family of warning system processors.