1 Introduction.- 2 Structure and bonding of diborane.- 2-1 Introduction.- 2-2 Elucidation of the structure of diborane.- 2-3 The bonding in diborane.- References.- Problems.- 3 Structures and bonding of some higher boranes and boron polyhedra.- 3-1 Introduction.- 3-2 The structures and bonding of some higher boranes.- 3-3 Topological treatment of boron hydrides.- 3-4 The structure and bonding of pentaborane(9), B5H9.- 3-5 Some examples of boron polyhedra.- References.- Problems.- 4 The general chemistry of the boron hydrides.- 4-1 Introduction : some thermodynamic data.- 4-2 Some vacuum manipulative techniques.- 4-3 Preparation and interconversions of the boron hydrides.- 4-4 Some reactions of diborane.- 4-5 Some reactions of higher boranes.- References.- Problems.- 5 Associated metal hydrides, alkyls, and aryls.- 5-1 Introduction.- 5-2 Associated metal hydrides.- 5-3 Some mixed hydrides.- 5-4 Some polynuclear hydrogen-bridged transition metal carbonyl hydride complexes.- 5-5 Organo-aluminium compounds.- 5-6 Some reactions of aluminium alkyls.- 5-7 Alkyl or aryl bridges involving gallium, indium, and thallium.- 5-8 Organo-beryllium and -magnesium compounds.- 5-9 Alkali metal alkyls.- 5-10 Some carbide structures.- References.- Problems.- 6 Carboranes.- 6-1 Introduction.- 6-2 The dicarba-closo-dodecaboranes, C2B10H12.- 6-3 Other dicarba-closo-boranes.- 6-4 Dicarba-nido-borane anions and their metal complexes.- 6-5 Species containing one cage carbon atom.- 6-6 Carboranes with more than two cage carbon atoms.- References.- Problems.- 7 Other examples of electron deficient bonding.- 7-1 Introduction.- 7-2 Electron deficient bridged carbonium ions.- 7-3 Transition metal cluster compounds.- 7-4 Transitionmetal-hydrocarbon ?-complexes.- 7-5 Electron deficient sigma bonding in electron rich species 195 References.- Problems.- Answers to Problems.