  Angle-resolved photoemission spectroscopy allows direct visualization and
experimental determination of the electronic structure of crystals in the
momentum space, including the precise characterization of the Fermi surface and
the superconducting order parameter. It is thus particularly suited for
investigating multiband systems such as the Fe-based superconductors. In this
review, we cover several aspects of these recently discovered materials that
have been addressed by this technique, with a special emphasis on their
superconducting gap and their Fermi surface topology. We provide sufficient
experimental evidence to support the reliability and the consistency of the
angle-resolved photoemission spectroscopy measurements over a wide range of
material compositions.
