The main object of this research was to show that by proper tapering of the circuit characteristics of a pulsed, high-power traveling-wave amplifier, long-persisting pulse-edge oscillations could be successfully eliminated. Several types of circuit tapering have been considered, and a particular one was chosen for this empirical study. The type of circuit taper, which appears to have several advantages over others for suppression of pulse-edge oscillations, has both the pi-mode frequency increased and the phase velocity for the passband frequencies decreased gradually toward the output end of the tube. The effect of circuit tapering on forward-wave amplification has also been studied. A method was introduced for calculating the performance and an increase in gain was predicted for the aforementioned taper by this method when the tube was operated beyond the small-signal level. This effect was also measured experimentally on a high-power tube constructed for this purpose. The effect of circuit tapering on tube efficiency has been studied qualitatively. By using the conventional velocity-phase diagram, the possibility of improving the efficiency is indicated. However, a different kind of circuit tapering other than that used for this study is required.