Louis Kahn, a pioneer of functionalist architecture, was born in Estonia but came with his family to the United States at the age of 4. A graduate of the University of Pennsylvania, he taught at Yale University from 1947 to 1957, during which time he became known for his addition to the Yale University Art Gallery (1951--53). This work, along with his design for the Richards Medical Research Building in Philadelphia (1957--61), gained him wide recognition. Kahn's international reputation as a major force in contemporary architecture came with his designs for the Salk Institute Laboratories in La Jolla, California (1959--65), the Kimbell Art Museum in Fort Worth, Texas, (1872) and the Paul Mellon Center for British Studies at Yale University (1969--72). From 1957 until his death, Kahn returned to his alma mater, the University of Pennsylvania, to teach. While there, he helped to start the so-called Philadelphia school of modernism. Kahn's designs, though simple, are powerfully complex and subtle at the same time.