In this book, the authors present current research in the study of the chemical properties, medicinal uses and environmental effects of manganese. Topics discussed include manganese in natural and artificial photosynthesis; manganese inhalation induces alterations comparable to Parkinson's symptoms; manganese complexes in lignin oxidation catalysis; the use of neuroimaging to explore cognitive function in welders exposed to manganese; sinter-alloying and properties of manganese steels; and excessive manganese exposure.