[en] During ion implantation into solids a number of important processes take place which alter the physical state of the near-surface region. A clear understanding of these processes and the resulting microstructural modifications is invaluable in utilizing ion implantation to engineer surfaces through the controlled modification of surface properties. This lecture summarizes current theoretical and experimental understanding in these areas. Basic ion implantation processes discussed include implantation fluence, stopping powers, ion range, damage energy, enhanced diffusion, ion mixing, and sputtering. The physical state of the implanted solid is then considered. Equilibrium and metastable implanted alloy formation is reviewed and the resulting structures are discussed. 81 references