Stephen W. Tsai is Professor Research Emeritus in the Department of Aeronautics & Astronautics, Stanford University. He received his B.E. and PhD. Engineering from Yale University in 1952 and 1961, respectively.  From 1952-1958 he was a Project Supervisor at Foster-Wheeler Corp.  From 1961-1963 he was a Research Scientist, Aeroneutronic Div of Ford Motor Company. From 1963-1965 he was a staff scientist, with the Air Force Materials Laboratory. From 1966-1968 he was Professor of Engineering & Director, Materials Research Lab, Washington Univ. In 1968 he came back to the Air Force Materials Laboratory as the Chief Scientist.  His has been working in composite materials over 50 years. He is a fellow of ASME and SAMPE, and a life member of the International Conference of Composite Materials, and the National Academy of Engineering. He is known for his failure criterion, books and training workshops on composite materials.