The protection of superconducting magnets can be narrowly considered as the problem of rapidly detecting an irreversible loss of superconductivity (quench) and converting the magnetic stored energy to thermal energy (dump) without permanent damage (protection). It can also be broadly considered as a method for avoiding all structural and electrical failure mechanisms through design, fabrication, and operation of a magnet. Energy dump and quench detection methods are reviewed. General magnet failure is surveyed historically.