Traditionally radio spectrum has been tightly regulated worldwide in order to manage interference among commercial and public wireless services. This “command and control” approach to spectrum allocation has been criticized in recent years as the cause of the following paradox: spectrum is viewed as a scarce resource, yet large portions of useful spectrum are typically idle. The Federal Communications Commission (FCC) in the U.S. has recognized that market mechanisms for spectrum sharing would likely lead to more efficient use of spectrum resources and provide for the current rapid growth in wireless systems and services. This talk will start with a general discussion of models for spectrum allocation, along with a description of how spectrum markets might be structured. We will then highlight some distributed techniques for interference management, and conclude with observations on how spectrum markets may affect the design of wireless systems.