Parallel Tempering: Theory, Applications, and New Perspectives
  We review the history of the parallel tempering simulation method. From its origins in data analysis, the parallel tempering method has become a standard workhorse of physiochemical simulations. We discuss the theory behind the method and its various generalizations. We mention a selected set of the many applications that have become possible with the introduction of parallel tempering and we suggest several promising avenues for future research. 
David J. Earl and Michael W. Deem