  These lectures give an introduction to the methods of conformal field theory
as applied to deriving certain results in two-dimensional critical percolation:
namely the probability that there exists at least one cluster connecting two
disjoint segments of the boundary of a simply connected region; and the mean
number of such clusters. No previous familiarity with conformal field theory is
assumed, but in the course of the argument many of its important concepts are
introduced in as simple a manner as possible. A brief account is also given of
some recent alternative approaches to deriving these kinds of result.
