This book is aimed at advanced undergraduates, graduate students and other researchers who possess an introductory background in materials physics and/or chemistry, and an interest in the physical and chemical properties of vel materials, especially transition metal oxides.New materials often exhibit vel phemena of great fundamental and techlogical importance. Contributing authors review the structural, physical and chemical properties of table 4d- and 5d-transition metal oxides discovered over the last 10 years. These materials exhibit extraordinary physical properties that differ significantly from those of the heavily studied 3d-transition metal oxides, mainly due to the relatively strong influence of the spin-orbit interaction and orbital order in 4d- and 5d materials. The immense growth in publications addressing the physical properties of these vel materials underlines the need to document recent advances and the current state of this field. This book includes overviews of the current experimental situation concerning these materials.