A review is given of recent developments in magnetic materials, including alloys for permanent magnets, “soft” materials having large initial and maximum permeabilities, and materials with constant permeability over a wide range of magnetizing force. Particular reference is made to dispersion-hardening alloys, the attainment of high degrees of purity in iron and iron alloys, improvements in sheet materials, the properties of nickel-irons, and of complex alloys based on them, after various thermal, magnetic, and mechanical treatments, and the characteristics of powdered materials.