IAU Colloquium 165, Dynamics and Astrometry of Natural and Artificial Celestial Bodies, was held in Poznan, Poland, in July 1996, bringing together over 200 scientists from 27 countries who discussed their work in 179 oral and poster presentations. The present volume contains 83 of the papers presented at the meeting. The meeting brought together specialists from diverse fields who focused on the very close collaboration between dynamics and astrometry, where one discipline contributes to the progress of the other. The oral sessions were organized into general categories pertaining to: solar system dynamics; new observational techniques, catalogues, and astrometry; dynamics and observational problems of artificial satellites and space debris; rotation of solar system objects; reference systems and astronomical standards; new mathematical techniques; and three all-day poster sessions. This volume is divided into seven parts, comprising 83 contributions and a list of participants.