William G. McCallum is a University Distinguished Professor of Mathematics and Head of the Department of Mathematics at the University of Arizona. Born in Sydney, Australia in 1956, he received his Ph.D. in Mathematics from Harvard University in 1984, under the supervision of Barry Mazur. After spending two years at the University of California, Berkeley, and one at the Mathematical Sciences Research Institute in Berkeley, he joined the faculty at the University of Arizona in 1987. In 1989 he joined the Harvard calculus consortium, and is the lead author of the consortium's multivariable calculus and college algebra texts. In 1993-94 he spent a year at the Institut des Hautes Etudes Scientifiques, and in 1995-96 he spent a year at the Institute for Advanced Study on a Centennial Fellowship from the American Mathematical Society. In 2005 he received the Director's Award for Distinguished Teaching Scholars from the National Science Foundation. In 2006 he founded the Institute for Mathematics and Education at the University of Arizona. He was Director of the Institute until 2009 and now chairs its advisory board. In 2009--2010 he led the work team that developed the NGA/CCSSO Common Core Math Standards. His professional interests include arithmetical algebraic geometry and mathematics education.