From 12 April to 14 April 1988, 120 of Gerard and Antoinette de Vaucouleurs's friends and colleagues gathered at the Institut d' Astrophysique in Paris to cel­ ebrate Gerard's 70th birthday and his remarkable career in Astronomy. The gathering also honored the memory of Antoinette (who died 29 August 1987 after a long illness) and her own no less remarkable career. This volume collects the 24 invited review papers and the 60 contributed poster papers presented at the meeting. Gerard de Vaucouleurs Gerard de Vaucouleurs was born on 25 April 1918 in Paris, where he spent his boyhood. He became an active amateur astronomer in the early 1930's, making extensive observations of Mars, Jupiter, and variable stars (including the bright supernova of 1937 in IC 4182). He also began life-long interests in astronomical photography and galaxy cataloguing during this period. In 1939, he met the director of the Paris transport system and an equally avid amateur astronomer, Julien Peridier. De Vaucouleurs worked at Peridier's private observatory at Le Houga in southwestern France on and off throughout the next decade. His undergraduate work was in mathematics, astronomy, and experimental physics; this, combined with his interest in observational astronomy, formed his life-long empirical approach to science. After spending 18 months in the French army early in 1939 - 41, Gerard returned to the Peridier observatory and then, in 1943, to his studies at the Sorbonne, where he met Antoinette.