The new technique of electron holography is reviewed. Using this technique, the phase distribution of an electron beam transmitted through a specimen is observed in the interference electron micrograph. The contour lines that appear can be interpreted as the thickness contours of a homogeneous specimen and as the magnetic lines of force of a ferromagnetic specimen. Several applications and future prospects are presented using this holographic interference method. [J. Cryst. Soc. Jpn. 26, 211 (1984) ] .
