  This is a survey article for "Handbook of Linear Algebra", 2nd ed., Chapman &
Hall/CRC, 2014. An informal introduction to representations of quivers and
finite dimensional algebras from a linear algebraist's point of view is given.
The notion of quiver representations is extended to representations of mixed
graphs, which permits one to study systems of linear mappings and bilinear or
sesquilinear forms. The problem of classifying such systems is reduced to the
problem of classifying systems of linear mappings.
