Strongly correlated electron phenomena in f-electron materials

A series of experiments on strongly correlated electron phenomena in f-electron materials, performed during the past three and one half decades, are briefly reviewed. The phenomena considered include the Kondo effect in superconductors, demagnetization of rare earth ions in metals, valence fluctuations of rare earth ions in metals, heavy fermion superconductors, and non-Fermi liquid behavior in f-electron systems. Recent experiments on heavy fermion behavior and unconventional superconductivity in the filled skutterudite compound PrOs4Sb12 are also discussed. The fundamental interactions responsible for the Kondo effect play a prominent role in the physics of strongly correlated electron phenomena in f-electron materials.