Evolution of Inorganic and Organometallic Photochemistry. Historical Perspectives and Commentary.- Intermolecular Energy and Electron Transfer Processes.- Photocatalysis: Definitions and Classifications.- Charge Transfer Excitation of Coordination Compounds. Generation of Reactive Intermediates.- Photoredox and Sensitization Processes involving Transition Metal Polypyridine Complexes.- Intramolecular Energy and Electron Transfer in Polynuclear Metal Complexes.- Photocatalysis: Reduction of CO2 and Water-Gas-Shift Reaction Photocatalyzed by 2,2'-bipyridine or 1,10-phenanthroline Cr(II), Ru(II), Re(I) and Ir(III) complexes.- Metal Complexes as Photosensitizers in Photoelectrochemical Cells.- Photosensitization by (Metallo)porphyrins: Formation and Photophysical Properties of Porphyrin Assemblies.- Photocatalytic and Photoredox Properties of Polyoxometalate Systems.- Photocatalytic Transformations of Organic Substrates Using Inorganic Salts and Complexes.- Photocatalysis Involving Metal Carbonyls.- Photocatalysis in C-H Activation.- Electron Donor-Acceptor Interactions and Photo-induced Electron Transfer of Organometallic Compounds.