New Theoretical Concepts for Understanding Organic Reactions : Springer : 9789401075398 : 9401075395 : 21 Oct 2011 : People who attended the NATO Advanced Study Institute (ASI) entitled NEW THEORETICAL CONCEPTS FOR UNDERSTANDING ORGANIC REAC­ TIONS held at Sant Feliu de Gufxols on the Costa Brava of Spain had a unique experience. They have seen the evolution of the field from qualitative arguments through the generation of Potential Energy Surfaces (PES) to the use of PES in molecular dynamics. The excellent lectures that were dedicated to the various aspects of Potential Energy Surfaces clearly revealed a colossal amount of ma­ terial that represents our current understanding of the overall problem. It is our hope that the present volume will recreate the excitement in the readers that we all experienced during the meeting in Spain. One can say, without too much exaggeration, that chemistry has become and exercise on potential energy surfaces (PES). Structural (position of the energy