Bombing by use of laser-guided weaponry is evolution, not revolution - aircraft have been bombing for more than 85 years, but a network of sensors in space or on the sea-bed that can track every move, without human involvement, may be revolution. This, and other technical advances, may enable intervention and prevention without conflict, certainly with non-lethal weaponry. The future structure of armed forces, the nature and size of defence industries, the potential risk of there being a single superpower, and many other matters, depend on how much the present and future change in military affairs is evolution and how much is genuine revolution. This study, based on report papers prepared for the Ministry of Defence and praised for their clarity, offers clear analysis of the debate for lay students of current and military affairs as well as professionals working in the fields of politics, science, security and military strategy and planning.