Land, water and air were the three dimensions in which wars were traditionally fought. The advent of electronic warfare (EW) ushered in the fourth dimension, which not only influenced the other three dimensions but also had an impact on shaping strategy and development of weapon systems and platforms. In fact, most of the systems developed since electronic warfare found its predominant place in conflicts, were inevitably intertwined with it. This book is an attempt to delve into, and analyse, the effects of electronic warfare on modern weapon systems and the subtle manner in which warfare has changed after its inception. For example the development of contemporary systems like stealth and unmanned aerial vehicles are outcomes of the need to evade the highly potent surface to air missiles and their associated radars, and the requirement to avoid human casualties. The latest victim of electronic warfare is the global positioning system (GPS). The impact of this navigational system has been stunning. Its employment in commercial and military applications has acquired gigantic proportions. However the system is highly vulnerable to jamming, a fact often ignored in the enthusiasm to climb the GPS bandwagon—something we should be wary of while developing our own systems. The author dwells on the effects of intentional and unintentional interference of electromagnetic energy on this very versatile system. Directed energy weapons (DEWs) are a new type of weapon system, never fielded before. They use electromagnetic energy (light and radio energy) to attack and destroy targets at the speed of light—years of research has made this possible. DEWs, which promise to transform what was in the realm science fiction into reality, have also been discussed. According to the author, electronic warfare in the future will metamorphose into more subtle and ingenious forms to get the better of the evolving systems like net centric warfare, cyber warfare, etc. Systems demonstrating this metamorphosis already exist. This book is a must read for all students and for the elite who exploit the electromagnetic spectrum to enable them to appreciate how this invisible weapon will affect their operations now and in the future.