Transmission Electron Microscope (TEM) is a very powerful tool for characterizing various types of materials. Using a light microscope, the imaging resolution is at several hundred nanometers, and for a Scanning Electron Microscope (SEM) at several nanometers. The imaging resolution of the TEM, however, can routinely reach several angstroms on a modem instrument. In addition, the TEM can also provide material structural information, since the electrons penetrate through the thin specimens, and chemical compositional information due to the strong electron-specimen atom interactions. This book provides a concise practical guide to the TEM user, starting from the beginner level, including upper-division undergraduates, graduates, researchers, and engineers, on how to learn TEM efficiently in a short period of time. It covers most of the areas using TEM, including the instrumentation, sample preparation, diffraction, imaging, analytical microscopy, and some newly developed advanced microscopy techniques. This book may serve as a textbook for a TEM course or workshop, or a reference book for the TEM user to improve their TEM skills.