Scattering of electrons is a fundamental phenomenon occurring either as a primary or secondary process whenever ionizing radiation interacts with matter. Energy deposition models, to study the interaction of radiation with matter and radiation damage, require scattering cross section data for all possible processes. Knowledge of electron scattering cross sections is therefore the most important and indispensable tool for the quantitative analysis of radiation impact phenomena. Electron impact ionization cross sections find practical applications in many branches of science viz. fusion edge plasmas, gas discharge plasmas, planetary, stellar and cemetery atmosphere, radiation chemistry, mass spectrometry and chemical analysis. Important applications of the basic knowledge of these collision processes include MHD (magneto hydrodynamics) power generation, electron lasers, the upper atmospheres of the earth and other planets and atmosphere of stars.