Modeling Tools: Population and Evolutionary Synthesis

I review the basic concepts for the spectrophotometric and chemical evolution of galaxies, contrast various approaches, and discuss their respective advantages and shortcomings, both for the interpretation of nearby and high redshift galaxies. The focus is on recent attempts to include gas and dust into galaxy evolution models and to account for the links among stars, gas and dust. Chemically consistent models are described that try to cope with extended stellar metallicity distributions observed in local galaxies and with subsolar abundances in young galaxies.