Vol. 1 - 5: The Hipparcos Input Catalogue. Vol. 6: Annex 1. Double and multiple stars. Vol. 7: Annex 2. The atlas of identification charts for faint stars. Annex 3. Identification charts for stars in galactic open clusters. Annex 4. Identification charts for stars in the Magellanic Clouds. The Hipparcos Input Catalogue was constructed as the observing programme for the European Space Agency's Hipparcos astrometry mission. The requirements of the project in terms of completeness, sky coverage, astrometric and photometric accuracy, as well as the necessary optimisation of the scientific impact, resulted in an extended effort to compile and homogenize existing data, to clarify sources and identifications and, where needed, to collect new da...