Articles in this book are based on talks given at the conference commemorating the 150th anniversary of the Washington University in St. Louis. The articles cover a wide range of important topics in mathematics, and are written by former and present faculty or graduates of the Washington University Department of Mathematics. The volume is prefaced by a brief history of the Washington University Department of Mathematics, a roster of those who received the PhD degree from the department, and a list of the Washington University Department of Mathematics faculty.