Princeton University enjoys a global reputation as a productive scholarly community that emphasizes excellence in teaching, where senior faculty teach freshmen while making seminal contributions to the advancement of learning. Less well known are the enduring friendships that flourish as a result of the union of research and teaching. This volume of memoirs provides a unique glimpse into the minds, classrooms, and private studies of some of the most distinguished professors of the twentieth century as seen by their former graduate students and junior colleagues. Ranging across the humanities, the hard sciences, the social sciences, and the applied sciences, something of the intellectual history of this century has been made accessible, enjoyable, and emphatically human by way of these portraits of Princeton faculty. The fifty faculty members who are the subjects of the essays made significant contributions to their fields of study. Each essay delivers a brief guided tour of "the state of the art, back when...," discusses the contributions made by these Princetonians, and offers personal vignettes and anecdotes at unexpected turns. The contributors were chosen based on their ability to inform their essays with a personal perspective. Each knew his or her subject as a teacher or mentor, and makes this person come alive for the reader. The result is an informative and emotional journey throughout the intellectual life of this century. Originally published in 1997. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.