Magnetars have been suggested as the most promising site for the origin of observed Soft Gamma-ray Repeaters (SGRs) and Anomalous X-ray Pulsars (AXPs). These objects are very different classes of neutron star. In this presentation, I overview recent observational progress on these objects, strongly magnetized isolated neutron stars, and introduce the magnetar model for SGRs and AXPs. In particular, I focus on the influence of strong magnetic fields on the properties and internal structures of magnetars. Finally, I introduce the magnetic domain model as a new mechanism for SGRs and AXPs.