From Marcel Duchamp's 'Portable Museum' (Boîte-en-valise) of the early 1940s to the latest interventions by artists in museums' displays, merchandise and educational activities, artists of the last seventy years have often turned their attention - both creatively and critically - to a reappraisal of the ideas underpinning the museum. Traditional methods of taxonomy, archiving, storage, and other aspects of curatorship have been variously appropriated, mimicked or reinterpreted. Assemblages of found objects or artists' possessions have served as an extension of the artist's studio, a storage place where both ideas and materials are evaluated. Many artists have exhibited their collections as an entity or a 'museum', thus contributing to a fresh understanding of the nature and role of the museum. The increasing trend towards collaborations between practising artists and museum curators has in some cases involved the rehanging of existing collections or redesigning of gallery spaces. In this way the probing instinct of the creative mind counterbalances the sense of permanence and order associated with the museum in a constructive dialogue involving elements of the past, present and future. The works included here, accompanied by quotations from the writings of individual artists, offer a wide-ranging coverage of projects by established and emerging figures alike, including Christian Boltanski, Sophie Calle, Tracey Emin, Hans Haacke, Donald Judd, Olafur Eliasson and Anish Kapoor. This edition includes artists' projects that make use of grand architectural spaces within the museum, as well as those that explore off-site locations and the internet, capitalizing on the idea of the 21st-century 'museum without walls'.