This second volume contains expanded versions of lecture notes for O. Schiffman's course, as well as ten research or survey articles, presented at the 2008 Summer School, Geometric Methods in Representation Theory (Grenoble, France, June 16-July 4, 2008). These texts give an overview of the representation theory of quivers, chiefly from a geometric perspective. The methods and results cover a wide range of mathematical domains: algebra and representation theory (Hall algebras, canonical and crystal bases, cluster categories, modular representations), algebraic geometry (flag varieties, moduli spaces, symplectic singularities), and homological methods (perverse sheaves, exceptional collections). In view of the diverseness of the topics, the reader is invited to consult the introductions of the texts for detailed overviews of their respective contents.