Pierre Deligne, Professor Emeritus, School of Mathematics. On the occasion of the sixty-first birthday of Pierre Deligne, the School of Mathematics will be hosting a four-day conference, "Geometry and Arithmetic" from October 17 to October 20, 2005. The objectives of the conference are to bring together scholars from a variety of mathematical fields with a common interest in the methods and ideas that Deligne has introduced into mathematics and to describe some recent advances in different areas of mathematics in a way that is accessible to non-experts from other fields. www.math.ias.edu/pd61