Abstract
A review has been made of the theories of the origin of x-ray satellite lines; the theories proposed since 1969 are dealt with in some detail. It seems certain that satellites are due to transitions in atoms which have an anomalous configuration of orbital electrons or are multiply ionized. The method of production of these configurations is the subject of all the theories. Recent results indicate that anomalous configurations and multiply ionized states can arise following a normal single ionization process.