a character on a group is a class function of positive type. for finite groups, the classification of characters is directly connected to the representation theory of the group and plays a key role in the classification of finite simple groups. based on the rigidity results of mostow, margulis, and zimmer, it was conjectured by connes that for lattices in higher rank lie groups the space of characters should be completely determined by the finite dimensional representations of the lattice. in this talk, i will give an introduction to this conjecture (which has now been solved in a number of cases), and i will discuss its relationship to ergodic theory, abstract harmonic analysis, invariant random subgroups, and von neumann algebras.