237 © e Author(s) 2020 P. Adey et al. (eds.), e Handbook of Displacement, https://doi.org/10.1007/978-3-030-47178-1_17 17 Technologies of Deportation William Walters Today the controversial practice of deportation casts a long shadow across the turbulent landscape of migration policies, border regimes, refugee protection, and population ows. For many decades deportation operated as merely one amongst a range of tools states had at their disposal for the purposes of immi- gration enforcement (Collyer 2012). Since the early 1990s it has acquired much greater prominence. In many countries the deportation of illegalised migrants, rejected asylum seekers, non-citizen oenders, and other categories of unwanted foreigners (whose number includes many long-settled residents) has become a large-scale operation, accounting for signicant levels of state funding, and employing specialised agencies and authorities. It is also a mode of human displacement that provokes widespread concern on the part of human rights groups and activists who see in deportation a violent activity that oers further evidence of the erosion of refugee and migrant protection regimes (Kanstroom 2007; Bloch and Schuster 2005; Khosravi 2009; Weber 2015; De Genova and Peutz 2010; Walters 2002). Scholarly interest in this deportation ‘turn’ (Gibney 2008) has grown accordingly to the point where deportation studies has emerged as a subeld of migration and security W. Walters (*) Carleton University, Ottawa, ON, Canada e-mail: william.walters@carleton.ca I thank Peter Adey for helpful comments on an earlier draft of this chapter, as well as Nicholas De Genova, Huub Dijstelbloem, Clara Lecadet, and Martina Tazzioli for our ongoing conversation about borders, migration, and politics.