In solid state physics and in materials science the investigation of the connection between the properties of solids and their microstructure is of major importance. For crystalline materials this connection is related to the lattice structure, and it can be shown convinc ingly that the material properties depend on deviations from the ideal lattice structure in the majority of cases. For this reason a reliable detection and analysis of defects in "nearly perfect" crystals is necessary, and a sufficient spatial resolution of the methods applied is required. Because electrons on the one hand...