Electron energy loss spectroscopy (ELS) is a vast subject with a long and honorable history. The problem of stopping power for high energy particles interested the earliest pioneers of quantum mechanics such as Bohr and Bethe, who laid the theoretical foun dations of the subject. The experimental origins might perhaps be traced to the original Franck-Hertz experiment. The modern field includes topics as diverse as low energy reflection electron energy loss studies of surface vibrational modes, the spectroscopy of gases and the modern theory of plasmon excitation in crystals. For the study of ELS in electron microscopy, several historically distinct areas of physics are relevant, including the theory of the Debye Waller factor for virtual inelastic scattering, the use of complex optical potentials, lattice dynamics for crystalline specimens and the theory of atomic ionisation for isolated atoms. However the field of electron energy loss spectroscopy contains few useful texts which can be recommended for students. With the recent appearance of Raether's and Egerton's hooks (see text for references), we have for the first time both a comprehensive review text-due to Raether-and a lucid introductory text which emphasizes experimental aspects-due to Egerton. Raether's text tends to emphasize the recent work on surface plasmons, while the strength of Egerton's book is its treatment of inner shell excitations for microanalysis, based on the use of atomic wavefunctions for crystal electrons.
