Jan H. Dort's work Ad:r>iaan Blaauw Meritus Emeritus Harry van der Laan 21 Jan Hendrik Dort and Dutch astronomy H. G. van Bueren 31 Dort's scientific importance on a world-wide scale Bengt Stromgren 39 Gart and international co-operation in astronomy D. H. Sadler 45 Reminiscences of the early nineteen-twenties Peter Van de Kamp 51 The first five years of Jan Dort at Leiden, Bart J. Bok 1924-1929 55 Early galactic structure Per Olof Lindblad 59 Early galactic radio astronomy at Kootwijk C. A. Muller 65 W. N. Christiansen Dort and his large radiotelescope 71 Ten years of discovery with Dort's...

On the occasion of the retirement of Ulrich Schwarz, a symposium was held in Groningen in May of 1996, celebrating his contributions to the study of the int- stellar medium, including his work on the high-velocity clouds. The coming together of many specialists in the latter ?eld prompted the idea of compiling a book c- taining their contributions, and summarizing the status of our understanding of the high-velocity cloud phenomenon. This seemed especially worthwhile at the time, since many exciting developments were taking place. After the discovery of some H i clouds with high velocities,...

Jan H. Dort's work Ad:r>iaan Blaauw Meritus Emeritus Harry van der Laan 21 Jan Hendrik Dort and Dutch astronomy H. G. van Bueren 31 Dort's scientific importance on a world-wide scale Bengt Stromgren 39 Gart and international co-operation in astronomy D. H. Sadler 45 Reminiscences of the early nineteen-twenties Peter Van de Kamp 51 The first five years of Jan Dort at Leiden, Bart J. Bok 1924-1929 55 Early galactic structure Per Olof Lindblad 59 Early galactic radio astronomy at Kootwijk C. A. Muller 65 W. N. Christiansen Dort and his large radiotelescope 71 Ten years of discovery with Dort's...

Adriaan Blaauw; Emeritus Professor of Astronomy at the Universities of Groningen and Leiden, former Directo.r of the Kapteyn Laboratory and of the European Southern Observatory, celebrated his 70th anniversary on 12 April 1984. To mark this event, an international Symposium was con vened on the subject "Birth and Evolution of Massive Stars and Stellar Groups," a subject which has played the leading role in Blaauw's scien tific research. The present volume contains the Scientific Proceedings of that Symposium. The meeting was organized by a Committee consisting of: W.H.W.M. Boland (Secretary),...