This latest version of the Atomic Line List, hosted by the Department of Physics and Astronomy at the University of Kentucky and maintained by Peter van Hoof of the Canadian Institute for Theoretical Astrophysics, provides "a compilation of approximately 923,000 allowed, inter-combination and forbidden atomic transitions." The database allows users to identify observed atomic absorption and emission features. The data are accessed through a query form, and the output format may be customized. The makers of this site request that researchers acknowledge the Atomic Line List (including the URL) if data are used in a paper.