Ionization and Transition Probabilities is the first volume in Atomic Inner Shell Processes which describes the relative status of the physics of atomic inner shells. Both volumes can be applied and used in various traditional scientific disciplines. Volume I consists of 11 chapters written by different authors, each an expert in the field. The book discusses mainly the inner-shell excitation by electrons, heavy-charged particles, and photons and the atomic excitation as seen in nuclear decay. The theory of radiative and radiationless transitions is also explored in terms of single-particle descriptions and many-body approaches. Other major concepts covered in this comprehensive volume include the developments in theory of multiple decay processes; transition energies and their calculations; and energy shifts that are results of chemical environment and hyperfine interactions. This first volume serves as a valuable reference to many scientists and researchers in various fields like atomic and nuclear physics, astrophysics, chemistry, surface and materials science, and engineering or radiation shields.