We report the near-edge x-ray absorption fine structure (NEXAFS) spectrum of a single layer of graphite (graphene) obtained by micromechanical cleavage of Highly Ordered Pyrolytic Graphite (HOPG) on a SiO2 substrate. We utilized a PhotoEmission Electron Microscope (PEEM) to separately study single-double-and few-layers graphene (FLG) samples. In single-layer graphene we observe a splitting of the π * resonance and a clear signature of the predicted interlayer state. The NEXAFS data illustrate the rapid evolution of the electronic structure with the increased number of layers.The recent discovery of a single sheet of graphite [1], called graphene, has opened up a new area of condensed matter physics.Graphene proves that materials just one atom thick may exist, with exciting prospects for applications. Its unusual electronic spectrum, where charge carriers mimic massless relativistic particles [2,3], also provides an unexpected bridge between condensed matter physics and quantum electrodynamics.The method to obtain single sheets of graphite [1], called micro-mechanical cleavage, allows easy production of sample with a typical size of few tens of microns, ideal for ballistic transport and Quantum Hall effect measurements, but inappropriate for many conventional spectroscopy investigations in Ultra High Vacuum (UHV) conditions. In the absence of new and more efficient ways to make graphene, samples obtained by micro-mechanical cleavage of bulk graphite are used in a limited class of experiments, where the size and the identification of thin flakes is possible. Indeed, after the cleavage with simple adhesive tape, graphene crystallites left on the SiO 2 substrate are extremely rare and hidden amongst hundreds of thicker flakes. Conventional surface science probes of the electronic and structural properties of materials, are then ruled out, unless they are coupled to a microscope. On the other hand, single-and few-layers graphene (FLG) samples have been grown epitaxially by chemical vapour deposition of hydrocarbons on metal substrates [4] and by thermal decomposition of SiC [5]. In both cases, the hybridization of graphene with the substrate is an unavoidable complication, although graphene on SiC preserves most of the electronic properties expected for a free layer [6,7,8].In this Letter we report the near-edge x-ray absorption fine structure (NEXAFS) spectra of a free layer of graphene, and of few-layers graphene (FLG) samples, obtained by a PhotoEmission Electron Microscope (PEEM) in UHV conditions. The spectrum of graphene exhibits a new structure below the π * resonance, reflecting its peculiar density of states (DOS) above the

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