The tremendous progress in olefin metathesis achieved during the last decade can hardly be overestimated. Due to the development of a new generation of well defined and high-performance organometallic catalysts, this reaction is rapidly evolving into one of the most versatile tools for advanced organic chemistry, natural product synthesis, fine chemical production and polymer sciences. Written by some of the leading experts in this field, this monograph intends to familiarize the reader with the most exciting developments and frontiers in this flourishing field of chemistry research.