The state of electron tube development in Germany at the beginning of the period is briefly reviewed. At higher frequencies the conventional grid-controlled triodes fail to work owing to lead and electron transit-time effects. It is shown how these effects can be reduced or made useful for the mechanism of the tubes. Compact triodes in metal-ceramic technology were developed for CW and pulse operation in the dm and cm bands. They have been combined with coaxial resonators. Finite transit-time was First utilized in 1920 in retarding field tubes. Beginning in 1924, zero and multisplit magnetrons with transmission line resonators were developed as oscillators. They were used in search receivers. Multicavity magnetrons were introduced in 1944. Although amplifier klystrons began to be developed in 1939, these were not used in wartime. However, a special klystron, the tunable Heil oscillator tube, came into practical use; a reflex klystron copied from captured equipment was modified and also used.