  We review efforts in string model building, focusing on the heterotic
orbifold compactifications. We survey how one can, starting from an explicit
string theory, obtain models which resemble Nature. These models exhibit the
standard model gauge group, three generations of standard model matter and an
appropriate Higgs sector. Unlike many unified models, these models do not
suffer from problems such as doublet-triplet splitting, too rapid proton decay
and the $\mu$ problem. Realistic patterns of fermion masses emerge, which are
partly explained by flavor symmetries, including their modular variants. We
comment on challenges and open questions.
