The monograph summarizes materials on the chemical and physical properties of simple metal oxides. Almost all solid phase stable metal oxides are considered. For a number of oxides of gold, titanium, molybdenum, platinum group metals, new data are provided on some chemical and catalytic properties. Particular attention is paid to the influence of structural and electronic factors on the change in electrical and magnetic properties and transitions such as dielectric-metal and semiconductor-metal. The structure of natural energy levels of simple metal oxides is considered in detail. Information on absorption, reflection, photoelectron spectra is given.