Magdeleine Hours, the 30-year director of the Laboratoire de recherche du musée du Louvre, is interviewed on the occasion of the publication of her book, <ine vie au Louvre</i>, (Editions Laffont). She describes her work in the laboratory where she manipulated (an allusion to her nickname gained from her familiarity with instruments that appeared ominous to the layman) the whole range of electromagnetic radiations, and discusses some examples of discoveries about paintings by Rembrandt, Titian, Van Gogh, and Picasso, this equipment made possible. She tells of the anxiety that prevailed among the staff during the transfer of the <i>Mona Lisa (La Gioconda)</i>to the National Gallery, Washington, in 1963, and related anecdotes. She answers the question of her contribution to the field of art history and in what way her findings modify our knowledge of works of art: analysis of their material composition and support brings knowledge of a physical nature that parallels our new way of linking the physical with the spiritual when treating human bodies. -- AATA