This paper is a gentle introduction to some recent results involving the
theory of gerbes over orbifolds for topologists, geometers and physicists. We
introduce gerbes on manifolds, orbifolds, the Dixmier-Douady class,
Beilinson-Deligne orbifold cohomology, Cheeger-Simons orbifold cohomology and
string connections.Comment: To appear in the Annales Mathematiques Blaise Pasca
