This book presents state-of-the-art coverage of the basic concepts of magnetization. The book focuses on electron-spin interaction, electron-spin-magnetic field interactions with or without angular dependent, magnetic properties with the dimension of particles or surrounding environment, proximity effects on core-shell structure or hybrid or composite and their applications. It also discusses recent advances in magnetic materials and its future scope. This book is of interest to students, researchers and professionals working in the area of materials science, especially magnetic materials and allied fields.