The rapid evolution of radio and radar systems for military use during World War II, and devices to counter them, led to a technological battle that neither the Axis nor the Allied powers could afford to lose. The result was a continual series of thrusts, parries and counter-thrusts, as first one side then the other sought to wrest the initiative in the struggle to control the other. This was a battle fought with strange-sounding weapons: 'Freya', 'Mandrel', 'Boozer' and 'Window'. It was a battle characterised by the bravery, self-sacrifice and skill of those who took part in it. During the war, however, and for many years after, electronic-warfare systems and their employment during the conflict remained closely guarded military secrets. When that veil of secrecy was finally lifted, the technicalities of the subject helped ensure that it remained beyond the reach of lay researchers and readers. Alfred Price, an aircrew officer with the RAF where he flew with V-Force and specialized in electronic warfare and air fighting tactics, was both inspired by the subject and in the unique position to lift the lid on this largely unexplored aspect of World War II. When it was first published in 1967, Instruments of Darkness came to be regarded as a standard reference work on this intriguing subject. Since its initial appearance, it has been expanded as important additional material has become available. This completely revised edition ends with the Japanese surrender in August 1945 and brings the analysis fully up to date in the light of what we now know.