We included in this book as many application examples as possible so that they can be used as criteria for judging what causes unsatisfactory image factors (hereinafter referred to as image disturbances). Although this edition does not describe all about image disturbances, it carries application photos to allow you to consider their causes. It is also important to correctly select the optimum observation conditions for various specimens. For instance, this book carries matters which are considered to be useful for using the instrument, such as the accelerating voltage, probe current and working distance (hereinafter abbreviated to WD).