Wu-chung Hsiang is unique among mathematicians both for his mastery of the important branch of topology and the forcefulness of his personality, as expressed in his incisive vision of what that subject is and should be. He is regarded as one of the great innovators in his field, honored as a prophetic guide to its highest goals, and as an unremitting critic of what is merely of passing interest.

Wu-chung was born in China in 1935 and emigrated with his family to Taiwan in 1949. At the time his father was an official in the Chiang Kai-shek government. Wu-chung received his B.A. from the National Taiwan University in 1957 and did his graduate studies at Princeton, under the guidance of Norman Steenrod. After receiving his Ph.D. in 1962, he joined the faculty at Yale University, reaching the rank of professor in 1968. In 1972 he returned to Princeton where he taught and did his research until his retirement in 2006. His example as a mathematician has inspired many others, not the least his two brothers, Wu-yi, who is now retired from the University of California-Berkeley, and Wu-teh, who is on the faculty of Syracuse University.

Wu-chung’s work has made him one of the most influential topologists of the second half of the 20^th century. His research ranges over the entire area of the topology of high-dimensional manifolds. Much of his work has centered on applications of surgery theory and algebraic K-theory. His 1969 paper with J.L. Shaneson on fake tori was a key technical step in the work of Kirby-Siebenmann on topological manifolds. With his brother Wu-yi and others, he pioneered the use of differential topological methods in compact transformation groups, becoming the first to use surgery theory to study actions of compact Lie groups on exotic spheres. Wu-chung worked with several different collaborators on applications of algebraic K-theory to homotopy groups of diffeomorphism groups and to the theory of stratified spaces. He did groundbreaking work with F.T. Farrell on the Novikov conjecture and the Borel conjecture. A highlight was their proof in 1981 of the Novikov conjecture for all nonpositively curved closed manifolds. Even more stunning was his 1989 paper with M. Bokstedt and I.B. Madsen in which they proved the K-theoristic analog of the Novikov conjecture for all groups. In 1996 Wu-chung went in a new direction, publishing an important paper with C.L. Curtis, M.H. Freedman, and R. Strong on four-dimensional manifolds. His enthusiastic and energetic approach to research has had a profound influence on his students and collaborators as well as on everyone else in the field.

Wu-chung chaired the mathematics department from 1982 to 1985, and afterward continued to take great interest in its welfare. He always has supported the idea that only individuals of the very highest caliber should be appointed to the department. Wu-chung has received many honors, among then the Sloan and Guggenheim fellowships, visiting professorships at the Universities of Amsterdam, Bonn, Stamford, and the University of California-Berkeley, together with election to membership of the Academia Sinica of the Republic of China.