In this paper, a review of Transmission Electron Microscopy (TEM) for the characterization of materials is presented. TEM is a technique which allow the crystallographic and chemical characterization of materials with high spatial resolution. Now, TEM allows the visualization of rows of atoms as well as defects like dislocations or staking faults. Chemical and crystallographic information in areas smaller than 1 nm can now be achieved with a Field Emission Gun Transmission Electron Microscope (FEGTEM). In this paper, a special emphasis is directed toward the characterization of electronic and magnetic materials. After an introduction of Transmission Electron Microscopy, all the Signals which are generated when an electron beam strike a thin foil in the TEM will be presented. This will allow to present all the techniques available in a TEM to perform materials characterization. All these techniques will be presented in the context of what they can do for materials characterization and their advantages as well as their limitations will be covered. The techniques which are covered are electron diffraction, the relation between image contrast and electron diffraction conditions in the context of defects characterization, Convergent Beam Electron Diffraction (CBED), x-ray microanalysis, Electron Energy Loss Spectroscopy (EELS), High-Resolution Transmission Electron Microscopy images (HRTEM) and the Z contrast. Specific examples of material characterization are presented for all these techniques. A description of the different electron sources is presented because they affect the spatial resolution of TEM.