In the modern world of ever smaller devices and nanotechnology, electron crystallography emerges as the most important method capable of determining the structure of minute objects down to the size of individual atoms. Crystals of only a few millionths of a millimetre are studied. This is the first textbook explaining how this is done. Great attention is given to symmetry in crystals and how it manifests itself in electron microscopy and electron diffraction, and how this symmetry can be determined and taken advantage of in achieving improved electron microscopy images and solving crystal structures from electron diffraction patterns. Theory and practice are combined; experimental images, diffraction patterns, formulae and numerical data are discussed in parallel, giving the reader a complete understanding of what goes on inside the "black boxes" of computer programs. This up-to-date textbook contains the newest techniques in electron crystallography, including detailed descriptions and explanations of the recent remarkable successes in determining the very complex structures of zeolites and intermetallics. The controversial issue of whether there is phase information present in electron micrsocopy images or not is also resolved once and for all. The extensive appendices include computer labs which have been used at various courses at Stockholm University and international schools in electron crystallography, with applications to the textbook. Students can download image processing programs and follow these lab instructions to get a hands-on experience of electron crystallography.