Interactions of photons and electrons with atoms, molecules, and ions are fundamental elementary processes in a wide variety of neutral or ionized gases in nature or laboratory. The data on the cross sections or related quantities for those processes are eagerly needed in many fields of application such as astrophysics, atmospheric science, plasma science, radiation physics and chemistry, etc. They are also important in understanding physical or chemical properties of atoms, molecules, and their ions. Volume I/17 provides cross section data and related quantitative information on the collisions of photons with atoms, electrons with atoms, and electrons with atomic ions. Subvolume I/17A deals with the interactions of photons and electrons with neutral atoms.