  Though the phenomenon of quantum-mechanical interference has been known for
many years, it still has many open questions. The present review discusses
specifically how the interference of resonances may and does work. We collect
data on the search for rare decay modes of well-known resonances that
demonstrate a wide variety of possible different manifestations of
interference. Some special kinds of resonance interference, not yet
sufficiently studied and understood, are also briefly considered. The
interference may give useful experimental procedures to search for new
resonances with arbitrary quantum numbers, even with exotic ones, and to
investigate their properties.
