The detection and control of combustion knock is an important function of the powertrain control module to ensure engine longevity and driver satisfaction. Electronic spark control systems are generally composed of a vibration sensor(s), knock detector, and spark control algorithm. These systems monitor the engine's operation for the occurrence of knock, and if present, modify the spark timing to eliminate knock. In this paper, the evolution of ESC products, calibration and analysis tools, and emerging research at Delco Electronics will be discussed. First, the prevalent theories of knock and the operation of knock detection systems are reviewed. Second, the family of knock detection products engineered for spark ignition engines are discussed in terms of functionality. Third, the specialized analysis and calibration tools developed to facilitate the deployment of these systems will be presented. Finally, an overview of the research efforts on the next generation of knock systems will be provided with an emphasis on rapid prototyping.