The advances in magnetic random access memory provide a remarkable showcase for the rapid development and application of nanodevices. Several aspects of state-of-the-art magnetic nanoscience and nanotechnology are developed and utilized in this single device. Current magnetic random access memory design is built upon the discovery and understanding of physics issues such as giant magnetoresistance, spin-dependent tunneling, exchange bias, and magnetic anisotropy in small elements. Successful magnetic random access memory development requires future research in some of the key areas involving nanotechnology. For example, the uniformity of the barrier thickness across the entire device and magnetic switching stability of a nanosized element are challenging issues that lie ahead. The spin degree of freedom of electrons is an added dimension that is both unique and useful in electronic transport and information technology. Nonvolatile, high-density, high-speed, and low-power magnetic random access memory is one of the first examples of the application of spintronics.