According to R.H. Crabtree, Metal Dihydrogen and -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'.