The year 1990, within the triennium covered by the present report, marked a number of significant anniversaries for the Central Bureau, including 70 years since its foundation at the Brussels Observatory, 25 years since the transfer of the Bureau’s operations to the Smithsonian Astrophysical Observatory (and 22 years of Dr. Marsden’s service as Director), and the issuance of the 5000th Circular. The amount of work done at the Bureau has increased enormously in this time, but especially within the past decade, as a result of the demands of modern astronomers and astrophysicists who are responding to the technological advances that have revolutionized observing and computing methods. At the same time methods of rapid communication have undergone a transformation that still continues. Appreciation is due for the support provided to the Bureau by the Smithsonian Astrophysical Observatory, but special gratitude must be expressed to Dr. Marsden and members of the staff and volunteers for their long hours of work and dedication to the needs of astronomers around the world for rapid access to information.