Thirty Years of Extragalactic H Ii Region Studies

I review a small part of the past thirty years of studies of extragalactic H II regions. Comparing a review of available results in 1975 to what we know today, we see a enormous increase in our knowledge of physical conditions and abundances in extragalactic H II regions, chemical evolution of galaxies, and the primordial helium fraction. Manuel Peimbert and Silvia Torres-Peimbert have made pioneering contributions to this field. Here I outline the progress in understanding extragalactic H II regions and highlight the Peimberts’ contributions.