GAIA -- Composition, Formation and Evolution of our Galaxy
  GAIA will provide a multi-colour photometric and astrometric census of some one billion compact sources, complete to 20th magnitude. In addition, spectra for radial velocities will be obtained for about 30 million stars brighter than V=17. The high spatial resolution and astrometric precision, 0.1arcsec and 10microarcsec to V=15, will not only quantify the distribution of mass and the stellar populations in the Galaxy, but make major advances in fundamental physics, cosmology and solar system science. GAIA is an ESA mission, scheduled for launch in mid-2011. A full description of the GAIA project and science case, fairly crediting the hundreds of contributors, is available in the project `Red Book' [ESA-SCI(2000)4]. A brief overview is provided by Perryman, de Boer, Gilmore, et al (2001). The www site is http://www.rssd.esa.int/GAIA/ 
Gerry Gilmore