The scattering cross section is the fundamental measure of the strength of a scattering interaction. All scattering in electron microscopy arises from the Coulomb interaction, and scattering cross sections, whether elastic or inelastic, will therefore all have common features. Simple forms of both elastic and inelastic cross sections are reviewed in the context of high resolution and analytical microscopy. Some recent developments, such as the calculation of Fano resonances in electron energy loss spectra of transition metals and rare earth elements are also discussed.