There has been enormous progress in our understanding of molybdenum and tungsten enzymes and relevant inorganic complexes of molybdenum and tungsten over the past twenty years. This set of three books provides a timely and comprehensive overview of the field and documents the latest research. Building on the first volume that focussed on biochemistry aspects, the second volume in the set focusses on the inorganic complexes that model the structures and reactivity of the active sites of each major group of molybdenum and tungsten enzymes. Special attention is given to synthetic strategies, reaction mechanism and chemical kinetics of these systems. The introductory chapter provides a useful overview and places the topic of the book into a wider context. This text will be a valuable reference to workers both inside and outside the field, including graduate students and young investigators interested in developing new research programs in this area.