Simply put magnetars are neutron stars whose magnetic fields dominate their emission, evolution and manifestations. In the late 1970s and early 1980s, a fleet of sensitive detectors of high-energy radiation uncovered two new phenomena, the soft-gamma repeater and the anomalous x-ray pulsar. Strongly magnetized neutron stars provide the most compelling model for both types of object, and observations over the past few years indicate that these phenomena are two manifestations of the same type of object. Soft-gamma repeaters exhibit quiescent emission similar to that of anomalous x-ray pulsars, and anomalous x-ray pulsars sometimes burst. What makes magnetars a hot topic of research is the rich variety of physical phenomena that strongly magnetized neutron stars exhibit.