Determining the elemental composition of surfaces is an essential measurement in characterizing solid surfaces. At present, many ap- proaches may be applied for measuring the elemental and molecular composition of a surface. Each method has particular strengths and limitations that often are directly connected to the physical processes involved. Typically, atoms and molecules on the surface and in the near surface region may be excited by photons, electrons, ions, or neutrals, and the detected particles are emitted, ejected, or scattered ions or electrons. The purpose of this book is to bring...