The book presents the characterization and classification of metallic biomaterials; with focus on titanium-based alloys, cobalt-based alloys, stainless steels and biodegradable alloys. Emphasis is placed on the synthesis, assessment of properties and medical applications such as multifunctional implants. The book references 423 original resources and includes their direct web link for in-depth reading. Keywords: Biomaterials, Classification, Titanium Alloys, Cobalt Alloys, Stainless Steels, Biodegradable Alloys, Medical Applications, Optimization of Metallic Biomaterials, Multifunctional Implants, Tissue Reactions, Toxicity of Metals, Inflammatory Reactions, Immunological Reactions, Sensibility, Allergy, Carcinogenic Effects, Ceramic Coatings, Ionic Implantation in Plasma, Biocompatibility.