The past decade has seen remarkable progress in the isolation and control of single spins in solid state devices. With electron spin coherence times in some materials now measured in seconds, single spins provide many features formerly unique to atomic systems in a form amenable to engineering complex integrated devices through semiconductor nanofabrication. In particular, the nitrogen-vacancy (NV) center in diamond has emerged as a promising single-spin system for wide-ranging applications in quantum computing, quantum communication, and nanoscale sensing. The NV center’s electronic spin can be initialized and measured optically, has millisecond coherence times at room temperature, and it provides access to individual nuclear spins with even better coherence properties. Recently, we have developed several techniques to control the NV center’s spin using coherent light-matter interactions – protocols that can be used to access other spin systems that lack the NV center’s unique optical addressability but might offer desirable properties for other applications. I will review the current state of this exciting field, describe several of our recent experiments, and outline the challenges and possibilities for the road ahead.