This investigation was concerned with the measurement and prediction of erosive burning. The theoretical models for erosive burning in composite propellants were reviewed. The experimental techniques which were cited in the literature for the measurement of erosive burning were also reviewed. Only the high-speed motion picture technique was found to have resolution sufficiently high to measure erosive burning accurately. The theory for the microwave burning rate measurement technique was also presented. Although this technique has never been applied to the measurement of erosive burning, it has high resolution and does not interfere with the internal flow over the propellant. For these reasons, microwave. interferometry was. recommended as the experimental method best suited to measure erosive burning. Utilizing the microwave technique, a preliminary design for an erosive burning tester was proposed. The proposed apparatus could generate crossflows from Mach 0.2 to Mach 1.0 over the propellant in the test section. A preliminary test plan for verifying the microwave measurement technique was presented. / M. S.