The Unified Astronomy Thesaurus Handbook provides a discussion of the value of a controlled vocabulary of astronomical keywords, a historical background on the Unified Astronomy Thesaurus (UAT), a description of the UAT and how to use and implement it, and a discussion of the benefits the UAT offers to the astronomy and astrophysics research community. The UAT Handbook is a live document that is continuously revised and updated as needed.
a community supported, open source project from the American Astronomical Society