David Hesk is Director of Radiochemistry in the Center for Drug Discovery at RTI International. After obtaining his Ph.D. studying hydrogen isotope exchange chemistry under the direction of Professor J.R. Jones, Dr. Hesk worked for 27 years in the Radiochemistry and Labeled Compound Synthesis groups at Schering-Plough and Merck where he was responsible for the synthesis, purification, and analysis of isotopically labelled compounds in support of pharmaceutical research. There he maintained his interest in hydrogen isotope exchange labelling (HIE) and published the first example of the application of Crabtree’s catalyst in HIE in 1995. Volker Derdau is the Head of the Centre of Excellence for Isotope Chemistry and Senior Distinguished Scientist at Sanofi, based in Germany. With over 25 years of experience in the pharmaceutical industry, he is an expert in the area of homogeneous catalysis, including radiochemistry and photocatalysis. He is author of over 70 articles and patents.