The goal of the investigation presented in this report is to study the inter-relationship between electrical conductivity, oxidation- reduction kinetics, defect structure, and composition of n- and p- type binary and ternary transition metal oxides. The experimental part of the investigation included specimen preparation, thermogravimetric measurements, X-ray diffraction, thermally stimulated current, oxygen diffusion, optical absorption, transmission electron microscopy, electrical conductivity, and Seebeck measurements. The systems studied or being studied are LaMnO{sub 3}-LaCrO{sub 3}-LaCoO{sub 3}, Y{sub 1-x}Ca{sub x}CrO{sub 3}, Sr-doped LaMnO{sub 3}, Y{sub 1-x}Ca{sub x}MnO{sub 3}, and Ba{sub 2}YCu{sub 3}O{sub 7-x}.