  Intermetallic compounds containing f-electron elements display a wealth of
superconducting phases, that are prime candidates for unconventional pairing
with complex order parameter symmetries. For instance, superconductivity has
been found at the border of magnetic order as well as deep within ferro- and
antiferromagnetically ordered states, suggesting that magnetism may promote
rather than destroy superconductivity. Superconductivity near valence
transitions, or in the vicinity of magneto-polar order are candidates for new
superconductive pairing interactions such as fluctuations of the conduction
electron density or the crystal electric field, respectively. The experimental
status of the study of the superconducting phases of f-electron compounds is
reviewed.
