This book presents an overview of the main metalair and metalsulfur batteries from fundamentals to applications. Recent technological trends are reviewed. It also offers a detailed analysis of these batteries at the material, component, and system levels. The book provides a systematic overview of the components, design, and integration, and discusses current technologies, achievements, and challenges, as well as future directions. Each chapter focuses on a particular battery type including zincair batteries, lithiumair batteries, aluminumair batteries, magnesiumair batteries, lithiumsulfur batteries, vanadiumair redox flow batteries, and metalsulfur batteries.