J. Arthur Seebach Jr (May 17, 1938 – December 3, 1996) was an American mathematician. Seebach studied Greek language as an undergraduate, making it a second major with mathematics. Seebach studied with A. I. Weinzweig at Northwestern University. He earned a Ph.D. with the thesis Cones and Homotopy in Categories. Seebach began to teach at Saint Olaf College in Northfield, Minnesota in 1965. He, his wife Linda A. Seebach, and Lynn A. Steen wrote an expository article "What is a Sheaf". The paper showed that a sheaf is useful in analysis, algebra, and geometry when considering germs of holomorphic functions, local rings, and differential forms. J. Arthur also wrote "Injectives and Homotopy".