Spin electronics exploits the angular momentum and magnetic moment of the electron to add functionality to electronic devices. The first generation of devices comprised magnetoresistive sensors and magnetic memory. The sensors have numerous applications, especially in digital recording. A second generation makes use of spin- currents and spin torque to switch the magnetization, induce oscillations or move domain walls. Conduction mechanisms are first summarized, and the main effects of spin torque, especially Slonczewski antidamping torque are discussed. The main materials used are briefly described. Magnetic logic and magnonics (the use of spin waves rather than conduction electrons to transfer magnetic information) are presented. Goals of spin electronics are efficient charge Û spin conversion, minimal energy consumption, scalability to nanometre dimensions and efficient non-volatile memory. Magnetic random-access memory (MRAM) is based on spin valve cells where magnetic field, spin-polarized current or pure spin current are used to switch the angular momentum. Magnetic recording uses moving media, semi-hard granular magnetic thin films or particles on hard discs or tape for semi-permanent storage of vast quantities of data. Write heads are miniature thin-film electromagnets, while read heads are usually spin-valves exhibiting giant magnetoresistance (GMR) or tunnelling magnetoresistance (TMR).