Magnetic storage media are a topic of great interest for technological and fundamental research. Examinations of nanostructured magnetic systems for storage media often aim at decreasing the pattern size, in order to enhance the possible information density in a given area. Here another approach is chosen: Intermediate magnetic states, occurring during magnetization reversal, which are stable at zero external field, can lead to quaternary or higher-order multilevel magnetic storage media. In this way, the storage density can be enhanced without decreasing the size of the magnetic nanoparticles. The book describes different nanostructured systems in which such additional stable states can be found in simulation and experiment, examines their magnetization reversal dynamics, and gives recommendations for shapes and materials of future nanostructured systems for data storage media.