I. Non-stoichiometry and Defect Structure.- The Control of Stoichiometry in Oxide Systems.- Phase Relations of Metal Oxides by Coulometric Titration.- Defect Structure and the Related Properties of UO2 and Doped UO2.- Defect Interactions, Extended Defects and Non-stoichiometry in Ceramic Oxides.- Computer Simulation Studies of Fe1?xO and Mn1?xO.- Mott-Littleton and Hartree-Fock Calculations on Defects in ?-Quartz.- Point Defect Structure of Chromium (III) Oxide.- Non-stoichiometry and Defect Structure of FeO.- Thermodynamic and Structural Evidence for the Presence of Defect Clusters in Some Non-stoichiometric Oxides.- Defect Chemistry of BaTiO3 and SrTiO3: Practical Aspects and Application to Electronic Ceramics.- Statistical Thermodynamics of Non-stoichiometric Oxides.- Electrical Conductivity Study of Cobalt Molybdate CoMoO4.- Electronic Structure of Transition Metal Impurities and of Surface Defects in SrTiO3.- Cation Distribution and Non-stoichiometry in MnCr2O4-NiCr2O4 Spinel Solid-Solutions.- II. Surface and Grain Boundary Phenomena.- Characterization of Defects on Oxide Surfaces and Their Impact on Surface Reactivity and Catalysis.- Interface Transport in Monoxides.- ZnO Interface Electrical Properties-Role of Oxygen Chemisorption.- Near-Surface Defect Structure of CoO in the Vicinity of the CoO/Co3O4 Phase Boundary.- Grain Boundary Phenomena in Some Electronic and Magnetic Ceramics.- Surface Oxygen Exchange in Bismuth Oxide Based Materials.- Defects and Reactivity at Oxide Surfaces: Experimental Aspects of the Interaction of Hydrogen, CO and CO2 with the NiO ?001? Surface311.- Nuclear Techniques in Surface Studies of Ceramics.- Calculated Grain Boundary Structures in NiO: Comparison with Experiment.- III. Transport Properties.- Oxygen Self Diffusion in Synthetic Rutile under Hydrothermal Conditions.- Short-Circuit Diffusion in ?Al2O3.- Oxygen Self-Diffusion in Volume and in Grain Boundaries of Cu2?xO.- Defect Structure and Diffusion in Mg2SiO4 (Forsterite) at High Temperature.- Influence of Chromium Segregation on the Transport Properties of Iron Monoxide.- Influence of Point Defects on the Near-Surface Diffusion in Some Oxide Systems.- IV. High Tc Oxide Superconductors.- Static Simulation Studies of La2CuO4.- Defects and Transport in YBa2Cu3O7?x.- Oxygen Nonstoichiometry and Chemical Diffusion Coefficient of Oxygen in Ba2YCu3O7?xO.- Point Defects and Transport in Small Polaron Systems.- Electronic Structure of High Tc Cuprates by Electron Spectroscopies.- Nonstoichiometry and Defect Equilibria in YBa2Cu3Ox.- V. Redox Processes.- Model Calculations of Metal Oxidation at Ambient Temperatures.- Point Defects and the Mechanisms Involved in the Reduction of Hematite into Magnetite.- Joining of Metallic Grains by Thermal Oxidation.- Impedance and Voltage Relaxation Studies of the Oxygen Sensor Systems Pt/O2/YSZ, Pt/O2/TiO2 and Pt/O2/?-Bi2O3.