Family background; undergraduate and graduate study at University of Birmingham; interruption of graduate studies by World War II in 1938; work on pulsed-radar transmitter at Ventron; thesis rechannelled into classified research by Marcus Oliphant; state of knowledge of high-powered tubes at Birmingham; plans for the magnetron with John T. Randall; comparison of Klystron and magnetron; improvements on and production of the magnetron for war use; other war work at Birmingham; Rudolf Peierls and Otto Frisch working on the atom bomb; the cyclotron; principal scientific officer of the Royal Naval Science Service at Baldock beginning 1948; contact with scientists from other countries; trip to United States; industrial uses of the magnetron; patent with the Admiralty.