India received the first of its contracted Airborne Warning and Control Systems (AWACS) on May 25, 2009, which was formally inducted by Defence Minister A.K. Antony on May 28, 2009. With the induction of the AWACS, India joined a club of only six other nations-the US, Russia, Britain, Japan, Australia and Turkey-that operate such a sophisticated system. The induction of AWACS was eagerly awaited mainly because of its capability to support the nation's politico military strategy in more ways than one. The dominant role of AWACS in air defence operations needs no emphasis, but in addition to air defence, its importance lies in the strategic capabilities that it engenders for national security. That, perhaps, is the reason for an increasing number of nations evaluating and acquiring different versions of airborne early warning systems to meet their national security requirements. The importance of AWACS for national security stems from its capability to provide strategic, operational and tactical solutions, and battlefield intelligence-all from one platform. In addition to typical air defence operations, AWACS have been utilised for power projection, peace enforcement, instruments of coercive diplomacy and as a strategic C4I and battle management platform , etc. There are many issues related to AWACS beyond air defence. Where does the operational role finish and strategic importance begin to take over? Are there areas of overlap and do both roles overshadow each other? What would be the effectiveness of AWACS in mountainous terrain? Will it be able to effectively support battlefield air interdiction missions, close air support missions and provide extensive early warning as is expected from AWACS? The next question could be, If the adversary also acquires AWACS, what would be the implications for a nation in conditions of AWACS symmetry? This book will attempt to cover the evolution and operational employment of AWACS in air defence operations and highlight its strategic role in national security. It would then compare AWACS with other air defence systems, study the constraints of AWACS operations in mountainous terrain, how many systems would be needed, the implications for India in case of AWACS symmetry, and some of the viable and cost effective options that will not replace AWACS, but complement its operations for a developing country like ours.