This contribution describes the properties of vanadium oxides and their applications, mainly as metal oxide electronics. It considers several issues related to the quantitative analysis of properties and applications of vanadium oxides. These issues will be considered in more detail in the following papers in terms of structural, defect chemistry, related electronic and electrical properties, and transport properties. It is focused on vanadium pentoxide thin films. This set of papers involves a significant collection of literature and unpublished data, describing the properties and potential practical applications of vanadium oxides and their critical analysis.