Metal Dihydrogen and σ Bond Complexes Background and Discovery of Dihydrogen Coordination Synthesis and General Properties of Dihydrogen Complexes Bonding and Activation of Dihydrogen and  Ligands: Theory versus Experiment Structural and NMR Studies of Dihydrogen Complexes Intramolecular Dynamics of Dihydrogen hydride Ligand Systems: Hydrogen Rotation Exchange and Quantum mechanical Effects Thermodynamics Kinetics and Isotope Effects of the Binding and Cleavage of  Ligands versus Classical Ligands Vibrational Studies of Coordinated Dihydrogen Reactions and Acidity of Dihydrogen Complexes Activation of Hydrogen and Related Small Molecules by Metalloenzymes and Sulfur Ligand Systems Coordination and Activation of Si H Ge H and Sn H Bonds C H Bond Coordination and Activation Coordination and Activation of B H and Other X H and X Y Bonds. According to R.H. Crabtree Metal Dihydrogen and sigma Bond Complexes is described as `the definitive account of twentieth century work in the area of sigma complexation. It covers not only Kubas discovery of dihydrogen coordination and the study of its structure and general properties but also discusses both the theoretical beliefs and experimental results of bonding and activation of dihydrogen on metal centers and the coordination and activation of C H B H X H and X Y bonds giving an overview of `one of the hottest areas in chemistry.