Recent progress in ligand field theory.- The ambident nature of cyanide.- Naturally occurring non-porphyrin iron compounds.- The chemistry and function of ferredoxin.- The transferrins.- Factors contributing to (b)-behaviour in acceptors.- Displacement reactions and the concept of soft and hard acids and bases.- Electric polarizability, innocent ligands and spectroscopic oxidation states.- The classification of acceptors and donors in inorganic reactions.