  The role of automorphisms of infinite-dimensional Lie algebras in conformal
field theory is examined. Two main types of applications are discussed; they
are related to the enhancement and reduction of symmetry, respectively. The
structures one encounters also appear in other areas of physics and
mathematics. In particular, they lead to two conjectures on the sub-bundle
structure of chiral blocks, and they are instrumental in the study of
conformally invariant boundary conditions.
