Frontiers in magnetic materials : from principles to material design and practical applications The book aims to provide comprehensive and practical guidance on magnetism and magnetic materials. It involves four parts focusing on fundamental magnetism hard magnetic materials soft magnetic materials and other functional magnetic materials. Part I highlights the ubiquity of magnetism and the close relationships between magnetic materials and our daily life. Perspectives on magnetism from Engineering and Physics are provided to introducing the two unit systems followed by the origin and categories of magnetisms. An introduction of important parameters during magnetization and magnetic measurement techniques are then provided to lay a solid foundation for the readers for better understanding of the design and development of different magnetic materials. Important magnetic materials are then introduced in the subsequent sections delivering an overview of design principles production technologies research developments and real world applications. For instance rare earth free and rare earth based hard magnetic materials as well as soft magnetic materials such as Fe based alloys composites and ferrites are discussed. Functional magnetic materials span a wide range which has been categorized into smart materials with magneto X effects together with magnetic materials for areas including electromagnetic wave absorption biomedicine catalysis and others. For these magnetic materials more emphasis is placed on the latest advances and interdisciplinary perspectives