Book excerpt: Principles of Electron Optic: Volume Three: Wave Optics, discusses this essential topic in microscopy to help readers understand the propagation of electrons from the source to the specimen, and through the latter (and from it) to the image plane of the instrument. In addition, it also explains interference phenomena, notably holography, and informal coherence theory. This third volume accompanies volumes one and two that cover new content on holography and interference, improved and new modes of image formation, aberration corrected imaging, simulation, and measurement, 3D-reconstruction, and more. The study of such beams forms the subject of electron optics, which divides naturally into geometrical optics where effects due to wavelength are neglected, with wave optics considered. - Includes authoritative coverage of the fundamental theory behind electron beams - Describes the interaction of electrons with solids and the information that can be obtained from electron-beam techniques - Addresses recent, relevant research topics, including new content on holography and interference, new modes of image formation, 3D reconstruction and aberration corrected imaging, simulation and measurement