Iron oxides are common compounds which are widespread in nature and constitute an important class of materials. Thinking about the importance of iron oxides for the humankind, magnetite, one of the most abundant magnetic minerals in earth's crust, comes to mind as a clear example. For many years, magnetite found a wide technological application range from navigation (compasses) to modern high density magnetic recording media. Moreover, iron oxides prepared in several nanostructure forms are also involved in environmental science, catalysis, biology, electronics, and other fields.