Due to their excellent magnetic characteristics, hard ferrites have many high-tech applications in such areas as permanent magnets, storage devices, HF Antenna and Spin Transmission. The present book reviews the present knowledge of these materials; their processing, characterization and potential applications. The book is also useful as an introductory text for students at the postgraduate research level. Keywords: Hard Ferrites, Synthesis, BaFe12O19, SrFe12O19, Magnetization, Miniaturization, EMI Shielding, Ferrofluids, Nanomaterials, Nano-Floating Gate, Permanent Magnets, Recording Media, High-Frequency Antenna, Radar Applications, Memory Devices. Spin Transmission, Spinel Model, Synthesis Methods.