Research into metal control in biological systems is undergoing rapid development. This new volume from the EIBC Book Series addresses how complex metal active sites are assembled and inserted into the metalloproteins that use them for catalysis. Metalloprotein Active Site Assembly provides a comprehensive description of the essential biosynthetic pathways for assembly of active sites covering all of the major biological transition metal components (Mn, Fe, Co, Ni, Mo), as well as the other inorganic components (e.g., S trafficking) and organic cofactors (e.g., heme, siroheme, cobalamin, molybdopterin) that make up the patchwork of evolved biological catalytic sites. The book compares and contrasts the biosynthetic assembly of active sites involving all biological metals. This has never been done before since this is a relatively new, fast-developing area of research. Only within the past several years have the tools been available that allow these pathways to be revealed. The various pathways are at different levels of understanding; none have been completely defined, but we are just now at the stage of being able to make meaningful comparisons among the pathways. All these articles will be published as part of the Encyclopedia of Inorganic and Bioinorganic Chemistry. Research into metal control in biological systems is undergoing rapid development. This new volume from the EIBC Book Series addresses how complex metal active sites are assembled and inserted into the metalloproteins that use them for catalysis. Metalloprotein Active Site Assembly provides a comprehensive description of the essential biosynthetic pathways for assembly of active sites covering all of the major biological transition metal components (Mn, Fe, Co, Ni, Mo), as well as the other inorganic components (e.g., S trafficking) and organic cofactors (e.g., heme, siroheme, cobalamin, molybdopterin) that make up the patchwork of evolved biological catalytic sites. The book compares and contrasts the biosynthetic assembly of active sites involving all biological metals. This has never been done before since this is a relatively new, fast-developing area of research. Only within the past several years have the tools been available that allow these pathways to be revealed. The various pathways are at different levels of understanding; none have been completely defined, but we are just now at the stage of being able to make meaningful comparisons among the pathways. All these articles will be published as part of the Encyclopedia of Inorganic and Bioinorganic Chemistry