  We present a new proof of a result due to Taubes: if X is a closed symplectic
four-manifold with b_+(X) > 1+b_1(X) and with some positive multiple of the
symplectic form a rational class, then the Poincare dual of the canonical class
of X may be represented by an embedded symplectic submanifold. The result
builds on the existence of Lefschetz pencils on symplectic four-manifolds. We
approach the topological problem of constructing submanifolds with locally
positive intersections via almost complex geometry. The crux of the argument is
that a Gromov invariant counting pseudoholomorphic sections of an associated
bundle of symmetric products is non-zero.
