A large literature has emerged on intelligence and war which integrates the topics and techniques of two disciplines: strategic studies and military history. The literature on intelligence and war is divided into theory and strategy; command, control, communications, and intelligence (C3I); sources; military estimates in peace; deception; conventional operations; strike; and counter-insurgency and guerilla warfare. Sun Tzu treats intelligence as central to all forms of power politics, and even defines strategy and warfare as “the way of deception.” On the other hand, C3I combines signals and data processing technology, command as thought, process and action, the training of people, and individual and bureaucratic modes of learning. Since 1914, the power of secret sources has risen dramatically in peace and war, revolutionizing the value of intelligence for operations, especially at sea. The strongest area in this study is signals intelligence. Meanwhile, the relationship of intelligence with war, and with power politics, overlaps on the matter of military estimates during peacetime. The literature on operational intelligence is strongest on World War II. However, analysts have particularly failed to differentiate the effect of intelligence on operations, from that on a key element of military power since 1914: strike warfare. In counter-insurgency, many types and levels of war and intelligence overlap, which include guerillas, conventional and strike forces, and politics in villages and capitals.