Magnetism plays a special role within dynamic processes in solids. In addition to the energy and linear momentum, the angular momentum must be conserved for magnetization reversal processes. This special feature leads to many interesting phenomena and gives the spin a special role in solids. In addition, the spin is strongly coupled to the charge through the fact that electrons are fermions; this manifests itself by the strong exchange interaction. In addition to the strong interest in fundamental questions on spin and charge dynamics, our modern information society would be unthinkable without nano-structured memory devices. The development goes towards smaller and faster devices which need to be stable against thermal fluctuations yet have switching times in the nanosecond range. The switching timescales must spread many orders of magnitude, from the switching time to the data retention time of (hopefully) many years. To achieve this, novel ways of magnetization switching beyond the well known application of a magnetic field along the desired magnetization are required.