James R. O’Neil is Professor Emeritus of Geochemistry at the University of Michigan. He received his B.S. at Loyola University (Chicago), M.S. at Carnegie-Mellon University and PhD. at the University of Chicago. After a post-doctoral appointment at the California Institute of Technology, he joined the U.S, Geological Survey where he established a stable isotope laboratory and spent 20 years engaged in experimental and theoretical calibrations of isotopic thermometers, and elucidating fundamental relations of stable isotope variations in deep crustal rocks, surficial carbonates, ore deposits, moon rocks, and natural waters. In 1988 he joined the faculty of the Department of Earth and Environmental Sciences at the University of Michigan where he focussed on studies of paleoclimate and the development of the oxygen isotope geochemistry of phosphates. He is a Geochemistry Fellow and the recipient of a "Forschungspreis" from the Alexander von Humboldt Foundation. He was awarded the Victor Moritz Goldschmidt Medal by the Geochemical Society of America in 2004.