This book reflects changes that have occurred during the last two decades in theoretical understanding and practical implementation of magnetic techniques in materials treatment. Research and development needs, based on the current strategic thinking and on principles of sustainable development are outlined. Development of magnetic separators based on powerful permanent magnetic materials, construction of reliable superconducting separators, design of efficient eddy-current separators and industrial implementation of magnetic carriers and magnetic fluids are examples of innovative changes that have taken place during the last twenty years. The book reflects the current technological trends and re-positions the research, development and practice of magnetic methods of material treatment in such areas as minerals beneficiation, recycling, waste treatment and biomedical and clinical applications.