Abstract : This research was directed towards developing new knowledge of combustion processes in liquid-propellant rocket engines. Attention was given to the combustion of different fuels, beginning with hydrogenoxygen but ultimately including multicomponent hydrocarbon mixtures representative of RP fuels, and to nonlinear processes of importance in combustion instability. Effects of detailed chemical kinetics on performance and stability were addressed by introducing systematically reduced chemistry that enables theoretical analyses to be completed thoroughly and accurately. The interactions between chemistry and turbulence were addressed, including the effects of the heat release on the turbulence. The orientation of the work was fundamental and aimed at predicting not only performance and acoustic response but also intrinsic instability. The results were intended to help to improve understanding of combustion mechanisms and combustion instabilities in liquid-propellant rocket motors. The most recent specific results concern induction times in hydrogen-oxygen mixtures and heat-release effects on turbulent mixing.