HAL is a tool for direct scientific communication between French researchers. Documents deposited in HAL are not subjected to any peer evaluation; but they should, however, be of sufficient quality to rate submission for publication in a specialised scientific journal. The multidisciplinary HAL open archive is intended for filing and dissemination of scientific research level articles, published and unpublished, and theses from teaching and French or foreign research institutions, public and private laboratories. The interface can be set to French or English.