In the post-quantum-mechanics era, few physicists have matched Julian Schwinger in contributions to and influence on the development of physics. A deep and provocative thinker Schwinger left his indelible mark on all areas of theoretical physics; an eloquent lecturer and immensely successful mentor he was gentle, intensely private, and know/n for being "modest about everything except his physics . This book is a collection of talks in memory of him by some of his contemporaries and his former students.