This morning we heard the sad news that Michael Asher died two days ago. Michael Asher’s work is based on direct and highly site-specific interactions with art institutions and their contexts. More exactly, Asher responds to the ways in which museums and exhibition spaces present themselves, or the objects they display, to their various publics. Informed in equal measure by historical research and contemporary exigencies, his art takes the form of subtle yet deliberate interventions – additions, subtractions or alterations – in particular environments. The highly diverse results are best categorized as sculpture, but a sculpture whose forms are shaped by deeply considered ideas rather than by physical gestures, and which rarely involves objects of the artist’s own making. In this sense Asher’s intellectual and creative enterprise has helped define, and continually expanded the implications of, the catch-all term ‘Conceptual art’, and it continues to have relevance for considerations of site-specificity and institutional critique.