Thirteen professors with a total of 371 years of teaching at Princeton have transferred to emeritus status, including two — Robert C. Darnton and John Suppe — who retired in 2007.

PETER R. GRANT, the Class of 1877 Professor of Zoology, is best known for collaborating with his wife, Rosemary, on the exploration of evolution by natural selection in a 35-year study of Charles Darwin’s finches on the Galapagos Islands. The findings showed that small-scale evolution in beak size and shape can occur in less than a year, far faster than previously had been believed for long-lived animals like birds. The Grants came to Princeton in 1985.

Molecular biology professor JOHN J. HOPFIELD, the Howard A. Prior Professor in the Life Sciences, has been recognized for his research in physics, chemistry, and biology. He received the Buckley Prize for research on emission and absorption of light by semiconductors; the work led to the founding of the semiconductor light-emitting diodes (LEDs) industry. In chemistry, Hopfield offered an explanation of the role of cooperativity in the binding of oxygen atoms to hemoglobin. In biology, his contributions include the invention of an associative neural network that demonstrates the wide difference in computing between the human brain and the computer.

During English professor WILLIAM L. HOWARTH’s 42 years at Princeton, he taught courses on intellectual history and textual criticism, added more than 50 new courses, pioneered humanities computing, supervised 100 dissertations and 256 senior theses, and led 51 alumni programs. He is an authority on Henry D. Thoreau, and he became the youngest-ever editor-in-chief of an NEH-sponsored project, the 25-volume writings of Thoreau. His later scholarship was highlighted by autobiography and literary journalism, and he introduced the University’s first courses on literary geography and environmental history, among others.

HISASHI KOBAYASHL *67 came to Princeton in 1986 as dean of the School of Engineering and Applied Science and the Sherman Fairchild University Professor. During his five years as dean, the number of permanent faculty in the school grew by 29 percent. After a year in Tokyo, he returned to Princeton as a professor of electrical engineering. Kobayashi has been honored for his invention of a high-density digital recording scheme known as PRML.

JOSEPH J. KOHN *56, a professor of mathematics since 1968, is known for his pioneering work on the interaction between particle differential equations and functions of several complex variables. He was chairman of the mathematics department several times, and he held the Henry Burchard Fine research chair from 2002 to 2003.

RALPH LERNER, the George Dutton ’27 Professor of Architecture, joined the faculty in 1984. While serving as dean of the School of Architecture from 1989-2002, he recruited significant new design faculty, strengthened the Ph.D. program in the history and theory of architecture, and consolidated the school’s emphasis on urban issues.

East Asian studies professor PERRY LINK JR. is noted as a scholar of modern Chinese literature and an authority on contemporary Chinese politics and intellectual life. After teaching at Princeton from 1973 to 1976, Link spent 13 years at UCLA before returning to the University in 1989. He taught first-year Chinese for two decades; with his colleague C.P. Chou, he founded and managed Princeton-in-Beijing, a total-immersion summer program. Several years after helping an outspoken scientist escape to the United States during the Tiananmen protests in 1989, Link was banned from China. In 2001, along with Andrew Nathan, Link obtained a set of secret government documents and translated and edited them as The Tiananmen Papers.

GUUST NOLET, the George J. Magee Professor of Geosciences and Geological Engineering and a faculty member since 1991, was a pioneer in seismic tomography — the imaging of the deep Earth — and designed the first portable digital seismic array for field studies of the Earth’s interior. He discovered thermal plumes deep in the Earth’s mantle, but may be best known to Princeton students for teaching the large GEO 210 course (“Earthquakes, Volcanoes, and Other Hazards”) nicknamed “shake and bake.”

Chemistry professor GIACINTO SCOLES came to Princeton in 1986 as the Donner Professor of Science. Much of his research focused on intermolecular forces and chemical-reaction dynamics. Scoles played an important role in the establishment of the Princeton Materials Institute, and he edited Atomic and Molecular Beam Methods.

ABRAHAM L. UDOVITCH, the Khedouri A. Zilkha Professor of Jewish Civilization in the Near East, joined the faculty in 1967 and served as chairman of the Department of Near Eastern Studies for 18 years. A scholar of the economic life of the medieval Near East and North Africa, Udovitch also has played an active role in attempts to end the Israeli-Palestinian conflict.

BASTIAAN C. VAN FRAASSEN, the McCosh Professor of Philosophy, came to Princeton in 1981. Van Fraassen is best known for writings on the philosophy of science in support of an unorthodox position that he called “constructive empiricism.” A colorful member of the department, he hosted legendary parties, inspiring the formation of a band that named itself the Van Fraassens. He also has published short stories and been an enthusiastic rock climber, and recently took up the trapeze.

ROBERT C. DARNTON, a history professor from 1968 until his departure last year to become the director of Harvard’s University Library, is a noted historian of publishing, books, and their readers. A crime reporter for The New York Times before he entered academe, Darnton believed that a historian should be a good storyteller and be accessible to a wide audience. A past president of the American Historical Association, he was a winner of the Guggenheim and MacArthur Prize fellowships.

JOHN SUPPE was the Blair Professor of Geology from 1988 to 2007, when he left Princeton to take a position at the National Taiwan University. Suppe, who joined the faculty in 1971, conducted research in Taiwan in 1978 that has applications in assessing earthquake hazards and in petroleum exploration and development. As chairman of the department, Suppe encouraged the application of microbiology and molecular biology to biologically mediated chemical processes in the Earth, such as global warming.