Heritage relies, to a large extent, on notions of endangerment and consequential attempts to arrest or reverse processes of loss and change. The papers in this special issue engage critically with this underlying orientation, exploring the social and cultural work which is produced through efforts to avert loss. In doing so, the papers also point towards alternative ways of valuing objects, places and practices which are not solely determined by notions of endangerment and risk. We suggest three general themes which connect critical investigation of these issues across the varied natural and cultural heritage contexts through which these papers work - the inevitability of loss; the politics of loss; and the potential in loss. These themes have significant implications not only for the future of natural and cultural heritage preservation, conservation and management but also in mapping out future research directions for critical heritage studies.