In crystalline solids, ductility and strength are known to be governed by generation of dislocations and their motion either by glide or climb. Meanwhile, a transmission electron microscope (TEM) has been developed as an indispensable tool for studying the micro-structures of crystalline solids used for various purposes. Topics related to the dislocation structures may be examined most critically by TEM observations, especially by stereo microscopy using a high voltage electron microscope.