This book covers fundamentals and recent advancements on conversion coatings for magnesium and its alloys. The contents are presented in two sections, respectively dealing with chemical and electrochemical conversion coatings. The chemical conversion coating section is further subdivided into inorganic conversion coatings, organic conversion coatings and advanced approaches/coatings. The section on electrochemical conversion coatings spans from fundamentals to state-of-the-art progress on electrochemical anodization and plasma electrolytic oxidation of magnesium and its alloys.