Correction of aberrations of an electron microscope by means of electron holography.

Electron holography using the M\"ollenstedt-type electron biprism [G. M\"ollenstedt and H. D\"uker, Z. Phys. 145, 377 (1956)] is now able to improve resolution and expressiveness of the electron microscope by subsequent correction of its aberrations and unique determination of amplitude and phase, as suggested by Gabor.