"Fundamental Astronomy and Solar System Dynamics", a program of invited papers honoring Professor Walter Fricke, who for thirty years has been Director of the Astronomisches Rechen lnstitut in Heidelberg, was held at the Thompson Conference Center of the University of Texas at Austin on Wednesday 27 March 1985 on the occasion of his seventieth birthday and retirement as Director of ARl. Professor Fricke's contributions to astronomy encompass the areas of galactic dynamics, radial velocities, stellar statistics. the fundamental reference system and the constant of precession. Participants were welcomed to the Uni versi ty of Texas by Professor J. Parker Lamb, Chairman of the Department of Aerospace Engineering and Engineering Mechanics. The presentations ranged from discussions of astrometric problems concerned with the reference system, the constant of precession, major and minor planet observations, planetary ephemerides and lunar and satellite laser ranging, to a study of disc galaxies in massive halos. The program concluded with a review of Professor Fricke's career. The three sessions were chaired by Victor G. Szebehely, Carol A. Williams and Jay H. Lieske. The participants in this meeting, and in the Division on Dynamical Astronomy meeting that followed, were happy that Professor Fricke was able to attend. His presence at these meetings, as well as his thoughtful comments, were greatly appreciated. We are pleased to acknowledge the support of the Center for Space Research, the Department of Astronomy and the Department of Aerospace Engineering and Engineering Mechanics of the University of Texas at Austin.

The Alexander von Humboldt Colloquium on Celestial Mechanics (sub titled "The Stability of Planetary Systems") was held in Ramsau, Styria, in the Austrian Alps, from March the 25th to the 31st, 1984. The dedication of the meeting to Alexander von Humboldt presented partici pants with the challenge that the discussions during the week should reflect the spirit of that great scientist of the last century, that the very many interesting ideas presented and developed during the sessions should be interpreted in the light of a broad v ew of astron omy and astrophysics. The topics of the meeting ranged from astrometric questions relating to the specification of inertial reference systems, motion of planets (including minor planets) and satellites, with the recurring topic of the search for criteria of stability of the systems, resonances, periodic orbits, and to the origin of the systems. Each session began with one or more invited review papers, followed by offered contributions and discussion. Three evening discussions were held, devoted respectively to inertial systems, to numerical integration techniques, and to cosmogonic problems and ring systems. On the evening of Wednesday, March 28th, a recital of chamber mus c was given by Bernhard Piberauer, on the violin, and Meinhard Prinz, on the piano."

"Fundamental Astronomy and Solar System Dynamics," a program of invited papers honoring Professor Walter Fricke, who for thirty years has been Director of the Astronomisches Rechen lnstitut in Heidelberg, was held at the Thompson Conference Center of the University of Texas at Austin on Wednesday 27 March 1985 on the occasion of his seventieth birthday and retirement as Director of ARl. Professor Fricke's contributions to astronomy encompass the areas of galactic dynamics, radial velocities, stellar statistics. the fundamental reference system and the constant of precession. Participants were welcomed to the Uni versi ty of Texas by Professor J. Parker Lamb, Chairman of the Department of Aerospace Engineering and Engineering Mechanics. The presentations ranged from discussions of astrometric problems concerned with the reference system, the constant of precession, major and minor planet observations, planetary ephemerides and lunar and satellite laser ranging, to a study of disc galaxies in massive halos. The program concluded with a review of Professor Fricke's career. The three sessions were chaired by Victor G. Szebehely, Carol A. Williams and Jay H. Lieske. The participants in this meeting, and in the Division on Dynamical Astronomy meeting that followed, were happy that Professor Fricke was able to attend. His presence at these meetings, as well as his thoughtful comments, were greatly appreciated. We are pleased to acknowledge the support of the Center for Space Research, the Department of Astronomy and the Department of Aerospace Engineering and Engineering Mechanics of the University of Texas at Austin.

B. G. Marsden Harvard-Smithsonian Center for Astrophysics Cambridge, MA 02138, U.S.A. !AU Symposium No. 81, "Dynamics of the Solar System", was held at the Hydrographic Office, Tokyo, Japan, during 23-26 May 1978. The Sym- posium was cosponsored by COSPAR and IUTAM, and generous financial sup- port was also provided by the Japan Society for the Promotion of Science. !AU sponsorship was through Commissions 4, 7 and 20, and the Scientific Organizing Committee consisted of the current Presidents, Vice Presi- dents and immediate Past Presidents of these Commissions: V. K. Abalakin, R. L. Duncombe, Y. Kozai, L. Kresak, B. G. Marsden (Chairman), P. J. Message, A. M. Sinzi, G. Sitarski and V. G. Szebehely. There were 64 participants from 15 countries, and 55 invited and contributed papers were read. The papers covered all branches of re- search on solar-system dynamics, and the eight sessions (chaired by Y. Kozai, V. G. Szebehely, W. Fricke, A. M. Sinzi, G. Sitarski, B. G.

B. G. Marsden Harvard-Smithsonian Center for Astrophysics Cambridge, MA 02138, U.S.A. !AU Symposium No. 81, "Dynamics of the Solar System", was held at the Hydrographic Office, Tokyo, Japan, during 23-26 May 1978. The Sym- posium was cosponsored by COSPAR and IUTAM, and generous financial sup- port was also provided by the Japan Society for the Promotion of Science. !AU sponsorship was through Commissions 4, 7 and 20, and the Scientific Organizing Committee consisted of the current Presidents, Vice Presi- dents and immediate Past Presidents of these Commissions: V. K. Abalakin, R. L. Duncombe, Y. Kozai, L. Kresak, B. G. Marsden (Chairman), P. J. Message, A. M. Sinzi, G. Sitarski and V. G. Szebehely. There were 64 participants from 15 countries, and 55 invited and contributed papers were read. The papers covered all branches of re- search on solar-system dynamics, and the eight sessions (chaired by Y. Kozai, V. G. Szebehely, W. Fricke, A. M. Sinzi, G. Sitarski, B. G.