Cosmic rays above 1014 eV

We briefly review the status of cosmic ray studies between 10(14) eV and the highest observed energies, namely a few times 10(20) eV. Because of the rather low incident fluxes in this energy range, the studies rely solely on ground based, large aperture detectors reconstructing the cosmic ray properties through the detection of the air-showers they generate by interacting with the atmosphere. We stress the fact that many issues such as the chemical composition of the cosmic rays, their acceleration mechanisms and the structures displayed in their energy spectrum are mostly open questions which may be answered by the next generation of experiments. (C) 2000 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.