* 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 physics. The great
advantage of the combination of electron optics and superconductivity in
these domains has been demonstrated in recent experiments. This
monograph is mainly concerned with electron micros- copy.
Superconductivity in high-energy electron optics is treated only
briefly, in Appendix A, since the author is little acquainted with the
details of the projects. Furthermore, the number of experiments as yet
carried out is small. In Appendix B, electron microscope studies of
basic superconductor phenomena are reviewed. This material is included,
even though it is only slightly connected with the main topic of the
book, since a breakthrough in this field may be possible by the
application of superconducting lenses.