John D. Roberts, 1918–2016, An Obituary-Tribute

John D. (“Jack”) Roberts, Institute Professor Emeritus and former Provost at the California Institute of Technology (Caltech), died on October 29, 2016 of complications of a stroke at the age of 98. He and his wife, Edith, made a big impact on the Caltech campus. An outstanding pioneer in physical chemistry, he introduced nuclear magnetic resonance (NMR) spectroscopy to organic chemistry, permitting chemists to determine the structures of complex biological molecules. He employed radioactive tracers to study thermal rearrangements of small-ring hydrocarbons to understand better how the reactions proceed on a mechanistic level. When, in 1956 at the age of 38, he was elected to the U.S. National Academy of Sciences, he was the youngest member elected at that time.