"Electron Holography" is a specialized book that focuses on the innovative technique of electron holography, a two-stage imaging method that utilizes both light and electrons. This method has proven to be valuable for fundamental physical experiments and high-precision measurements in microscopy. The second edition of the book, which incorporates new findings, provides a comprehensive overview of the current state of electron holography. The author, Akira Tonomura, highlights the principles, techniques, and applications of this technology, which has been continuously developed in recent years. The book is aimed at scientists and engineers who wish to enter this fascinating field of research and offers valuable insights into the possibilities this technique opens up for observing and measuring microscopic objects and fields. The use of extremely short wavelengths of electrons allows for the exploration of areas that are inaccessible with other techniques, thus having far-reaching implications for various scientific and industrial applications.