These twelve lectures on relativity in celestial mechanics and astrometry have been delivered for students specializing in astronomy in Saint-Petersburg State University (Russia) by V.A. Brumberg. They are based mainly on the 1991 book of the author "Essential relativistic celestial mechanics" and later papers on application of general relativity in positional astronomy published in connection with the IAU resolutions on reference systems and time scales based on general relativity.
The aim of these lectures was to prepare students for work in the field of relativistic celestial mechanics and astrometry.