Major advances spanning several orders of magnitude in sensitivity are anticipated in the current round of experiments dealing with rare kaon decays. Observations of allowed processes, like and , shed light on detailed aspects of the standard model. New sources of T or CP violation could be manifested by measurements of muon polarization in K → πμνμ and decays and by studies of reactions like . Evidence for new particles and new interactions could appear in advanced efforts to observe K → πxx′ and K → πx decays, where x and x′ represent hypothetical neutral particles, and in searches for lepton flavor violating processes and K+ → π+μe. The experiments are reviewed and their theoretical context is discussed.