Volume III/27 covers the magnetic properties of inorganic compounds based on transition elements. It can therefore be considered as a supplement to volumes III/4 and III/12 Magnetic and other properties of magnetic oxides and related compounds which appeared in 1970 and in the period 1978 - 1982 respectively. In a way this volume also forms a counterpart to volume III/19, in which the magnetic properties of metals, alloys and metallic compounds are compiled. The first subvolume, III/27a, which appeared in late 1988, deals with the magnetic properties of pnictides and chalcogenides which contain 3d elements. Subvolume III/27d treats oxy-spinels. In subvolume III/27e oxidic compounds with the garnet structure are considered; they include both iron and non-iron substances. The present subvolume III/27g covers binary oxides based on d-transition elements, oxides with trirutile and pyrochlore structure and oxides with a hexagonal crystal structure. The major part of the latter group is an updating of the compilations which appeared already in the Landolt-Börnstein subvolumes III/4b and III/12c. A preliminary survey of the contents of all subvolumes planned for Landolt-Börnstein III/27 is printed on the inside of the front cover. Physical and chemical properties which are of interest in connection with the magnetism of the oxides, have been given the necessary attention.