[T. A. Gardner]

I would think I should revise my previous list (pg 12) to:

Electronics (replaces FM Radio and radar) to a more general category including television, sonar, computers, etc.

and

Solid state devices including the transistor.

On the Cavity magnetron: This device is just an improvement of magnetrons in general and were generally known prewar. The major improvements the British made in this device were A. Strapping. B. The use of multiple smaller cavities in addition to the main cavity and their size and shape, and C. The use of a metal casing and addition of a larger external magnet to induce higher power out of the component.
The Japanese were experimenting with millimeter wave radar as early as 1939, ahead of the British using lower power magnetrons so, this can hardly be called some magnificant invention that came "out of the blue." If anything, the Germans were really behind the learning curve for not discovering something many other nations were already aware of.