The lecture I am going to give attempts to cover, in forty-five minutes a subject that really merits a series of lectures. This, of course, displays a fitting disregard for minor difficulties, of which, I am sure, the dauntless spirit of Sir George Cayley would have approved.

The broad title permits consideration of all methods of intelligence gathering from the air, including the more widely known optical photographic systems, and has been deliberately selected for this purpose. To avoid clumsy and longwinded definitions I will frequently have recourse to the the use of “in” terms such as Sensor, Multi-Sensor, Exploitation, Environment and many others.