  The classical Green's function associated to a simply connected domain in the
complex plane is easily expressed in terms of a Riemann mapping function. The
purpose of this paper is to express the Green's function of a finitely
connected domain in the plane in terms of a single Ahlfors mapping of the
domain, which is a proper holomorphic mapping of the domain onto the unit disc
that is the analogue of the Riemann map in the multiply connected setting.
