  The unusual transport properties of graphene are the direct consequence of a
peculiar bandstructure near the Dirac point. We determine the shape of the pi
bands and their characteristic splitting, and the transition from a pure 2D to
quasi-2D behavior for 1 to 4 layers of graphene by angle-resolved
photoemission. By exploiting the sensitivity of the pi bands to the electronic
potential, we derive the layer-dependent carrier concentration, screening
length and strength of interlayer interaction by comparison with tight binding
calculations, yielding a comprehensive description of multilayer graphene's
electronic structure.
