In this book, the authors present current research in the study of the occurrence, uses and properties of cobalt. Topics discussed include the microwave and magnetic properties of cobalt-containing magnetophotonic crystals; promoted cobalt silica gel catalysts for Fischer-Tropsch synthesis; cobalt and its compounds in oxidation-reduction processes of environmental catalysis; the nature of cobalt species in Co-zeolites used for the selective catalytic reduction of NOx with hydrocarbons; cobalt toxicity in Escherichia coli; cobalt speciation in aqueous solution and sorbents on the basis of natural dolomite for cobalt removal; the morphology, microstructure, structural and thermal properties of Co powder; comparison of cobalt and iron perovskite-based catalysts for WGSR; direct patterning of cobalt nanostructures using focused electron beam induced deposition; cobalt catalysts applied in ethanol reforming reactions; combustion synthesis of cobalt compounds; AB initio study of energetics and properties of cobalt interlayers in WC/Co alloys; anisotropic lattice distortion of composite materials of chiral Cu(II)-Co(III) or Cu(II) complexes and TiO2; and the chemical process of recovering cyanides as cyanide-bridged Cu(II)-Co(III)/Fe(III) bimetallic assemblies from preparation of semiconductors for solar cells.