Instrumental Optics: Electrostatic Lenses. Magnetic Lenses. Electron Mirrors. Cathode Lenses and Field Emission Microscopy. Quadrupole Lenses. Deflection Systems. Aberration Correction and Beam Intensity Distribution (Caustics): Aberration Correction. Caustics and Their Applications. Electron Guns: General Features of Electron Guns. Theory of Electron Emission. Pointed Cathodes without Space Charge. Space Charge Effects. Brightness. Emittance. The Boersch Effect. Complete Electron Guns. Systems with a Curved Optic Axis: General Curvilinear Systems. Magnetic Sector Fields. Unified Theories of Ion Optical Systems.