  These two lectures cover some of the advances that underpin recent progress
in deriving continuum solutions from the exact renormalization group. We
concentrate on concepts and on exact non-perturbative statements, but in the
process will describe how real non-perturbative calculations can be done,
particularly within derivative expansion approximations. An effort has been
made to keep the lectures pedagogical and self-contained. Topics covered are
the derivation of the flow equations, their equivalence, continuum limits,
perturbation theory, truncations, derivative expansions, identification of
fixed points and eigenoperators, and the role of reparametrization invariance.
Some new material is included, in particular a demonstration of
non-perturbative renormalizability, and a discussion of ultraviolet
renormalons.
