An introduction to practical astrometry, dealing with the determination
of positions, motions, distances and dimensions of celestial bodies
ranging from quasars to artificial satellites. For this 2nd edition, the
release of the Hipparcos and Tycho catalogs, the rise in CCD astrometry
and the adoption of a new celestial reference frame by the IAU led to a
significant modification of the text. And, especially, the outlook for
astrometry has been completely rewritten.