The observational and interpretive tools for the study of chemical evolution are starting to be mature enough that they can be applied with some confidence to extra-galactic systems and integrated populations at increasingly high redshift. This book is devoted to the study of the interplay between different methods of measuring chemical abundances with astrophysical models. Studies of chemical abundances and evolution from stars, inter-stellar medium and local group galaxies at zero redshift to distant galaxies, clusters of galaxies and inter-galactic medium at high redshift are presented. There are also synopses on progress in instrumentation for abundance determination.