  VizieR is a database grouping in an homogeneous way thousands of astronomical
catalogues gathered since decades by the Centre de Donnees de Strasbourg (CDS)
and participating institutes. The history and current status of this large
collection is briefly presented, and the way these catalogues are being
standardized to fit in the VizieR system is described. The architecture of the
database is then presented, with emphasis on the management of links and of
accesses to very large catalogues. Several query interfaces are currently
available, making use of the ASU protocol, for browsing purposes or for use by
other data processing systems such as visualisation tools.
