Fernando P. Cossio is a full professor of Organic Chemistry at the University of the Basque Country (UPV/EHU, Spain) and at the Donostia International Physics Center in San Sebastian (Spain). He studied Chemistry at the Universidad de Zaragoza (Spain) and received his Ph.D. at UPV/EHU in 1986 with Prof. C. Palomo. He there became Associate Professor in 1988 and Full Professor in 2002. He has been the Dean of the UPV/EHU Faculty of Chemistry, Vice-President for Research and International Relations at the same university (2001-2004), and President of the Executive Committee of Ikerbasque, the Basque Foundation for Science (2009). He has authored ca. 200 papers, books, and book chapters as well as 14 patents. His research interests include pericyclic reactions, C-C bond forming reactions, unusual species or reaction conditions, catalysis, and medicinal chemistry. Kendall N. Houk is the Saul Winstein Chair in Organic Chemistry at the University of California, Los Angeles (UCLA), since 2009. He received his Ph.D. at Harvard University, USA, working with Prof. R.B. Woodward. He taught at Louisiana State University and the University of Pittsburgh, USA, before moving to UCLA in 1986. From 1988-1990, he was Director of the Chemistry Division of the National Science Foundation. He was Chairman of the UCLA Department of Chemistry and Biochemistry from 1991-1994. He has won numerous awards, such as ACS Arthur C. Cope Scholar Award, the ACS James Flack Norris Award in Physical Organic Chemistry, the Schrodinger Meal of the World Association of Theoretical and Computational Chemists (WATOC), and the ACS Award for Computers in Chemical and Pharmaceutical Sciences. He has been elected to the American Academy of Arts and Sciences, the International Academy of Quantum Molecular Sciences, and the National Academy of Sciences. He has published nearly 1000 articles. His research group is involved in the development of rules to understand reactivity, computer modeling of complex organic reactions, and experimental tests of the predictions of theory.