Professor Figgis has advanced knowledge of the nature of the metal-ligand bond. He was one of the first to apply ligand field theory to the magnetic properties of transition metal complexes, particularly their temperature dependence and anisotropic behaviour. His application of nuclear magnetic resonance spectroscopy to inorganic systems, employing nuclei other than the proton (1H) and use of X-ray diffraction for studying bonding was seminal. More recently, he has applied high precision X-ray and polarised neutron diffraction in a complementary programme to give 3-dimensional information on valence electron charge and spin distributions, and with advanced ab-initio molecular orbital calculations has given a much more critical account of the metal-ligand bond than any previously available.