* Electron optics involves the influence of electric and magnetic fields on electron beams. In those electron optical instruments utilizing magnetic fields, a replacement of the conventional, i.e .. nonsuperconducting, electron optical parts, is worth considering if the outstanding magnetic properties of superconductors can improve the systems. However, the use of superconductors demands complicated cryogenic techniques and this, of course, dampens enthusiasm. There are fields, however, where there are extreme requirements on the optical systems, namely, electron microscopy and high-energy...