Can we believe the strong-line abundances in giant HII regions and
  emission-line galaxies?
  This review is not a compendium of strong-line methods to derive abundances
in giant HII regions. It is mostly intended for readers who wish to use such
methods but do not have a solid background on the physics of HII regions. It is
also meant to encourage those using abundance results published in the
literature to think more thoroughly about the validity of these results.
