Spintronics encompasses the ever-evolving field of magnetic electronics. It is an applied discipline that is so forward-looking that much of the research that supports it is at the center of basic condensed matter physics. This review provides a perspective on recent developments in switching magnetic moments by spin-polarized currents, electric fields, and photonic fields. Developments in the field continue to be strongly dependent on the exploration and discovery of novel material systems. An array of novel transport and thermoelectric effects dependent on the interplay between spin and charge currents have been explored theoretically and experimentally in recent years. The review highlights select areas that hold promise for future investigation and attempts to unify and further inform the field. Copyright © 2010 by Annual Reviews. All rights reserved.