International audienceHow can we define disability and handicap? What are their different forms? What are the figures for the persons concerned? This paper reviews the key conceptual advances and classification developments as well as new French nationwide surveys on disability. Any attempt at defining what is handicap gives rise to heated debates. This layman word initially originating from the turf language has been prevailing in the medico-social field for the last fifty years. The French 2005 Law on disability has now provided a legal definition inspired by the recommendations of the World Health Organization (WHO). For thirty years, following the pioneering work of Wood, international classifications of disability have been an importan...