Stephen Castles' passing presents a bittersweet opportunity for reflection. A diminutive man but towering scholarly figure, his personal generosity and extraordinary scope of research will have a lasting impact on many of us. That impact extends beyond the content of his publications, teaching and collegiality to ‘migration studies’, a field he pioneered more than perhaps any other single scholar. Through his own work, as a supervisor, and as an institution builder, he has shaped a generation. Perhaps two. With more to come. As someone who has long collaborated with (and who now works within) the somewhat bewildering migration studies universe he helped forge at the University of Oxford, I daily feel and hear echoes of his work. Castles' substantial efforts to locate studies of displacement and migration on sound conceptual and methodological foundations have provided a blueprint for similar initiatives around the world. His influence on the Centre for Migration Policy and Society (COMPAS) and the International Migration Institute – both at Oxford – manifested his commitment to social scientific research on migration and mobility that corrodes popular myths and political misconceptions. Even while his work was expansive in its ambition and scope, it rarely failed to centre the implications for those who moved, those unable to do so, or the communities transformed by human mobility. His dedication to building spaces for and inspiring methodologically sound, morally grounded, university-based research is more important than ever. Immigration and displacement are now at the centre of political debates across the world. In response, migration research institutes and researchers have blossomed like desert flowers after heavy rains. Many are nourished with funding dedicated to ‘managing’ migration in ways ‘safe and orderly.’ While migrant safety and welfare is often a stated goal, these bodies form part of a political economy of knowledge potentially undermining the kind of critical scholarly enterprise Castles envisioned. Instead, ‘migration studies’ may follow the course of Victorian anthropology, legitimized (or at least funded) by state and non-state actors with neo-imperial ambitions. The field already rewards those proving useful to powerful states and state supported agencies. Academic metrics privileging ‘impact’ only exacerbates these trends. In this space, Castles' perennial efforts to highlight the human consequences of migration, drawing attention to multiple forms of labour exploitation, resource extraction, ethnic reformulation, and racial discrimination were important counter measures to these tendencies. Many of us remain inspired by his efforts to denaturalize the technocratic language of economics and bureaucrats who seek to depoliticize, dehumanize or criminalize the geographic mobility of people from many of the world's disadvantaged regions. In short, Castles has helped define Migration Studies as a delimited subject and field of study within the academy. Many of us – myself included – would be marginalized within our home disciplines (especially those from Political Science) rather than part of a global community of interdisciplinary, often publicly engaged scholars. As with other categorically determined fields of enquiry–gender/women studies; queer studies; race/ethnic studies to name a few–it is less method or theory that provides the glue. Rather, the field is held together by broad thematic interests and compelling normative commitments. As noted above, it is in the ethos of its field, its habitus, its boundaries, and the very concepts that define it – that Castles' legacy is perhaps most pronounced. Yet this is not a legacy beyond critique. Stephen Castle's intellectual bequests have undoubtedly inspired and enabled migration research. They also bear the marks of the man he was, the time in which he lived, and his personal ideological and intellectual commitments. In so doing, the field he helped establish has helped define, replicate and reinforce many of the epistemological and institutional configurations that limit the field. It has bequeathed a form of Eurocentrism that geographically centres the field in Europe, is largely framed by European (or ‘northern’ concerns), and remains dominated by scholars educated, based, or oriented towards their institutions. Given Castles' position as one of the field's primary progenitors, Castles' commitments subsequently become reference points and metrics for a generation of scholars. Having spent the greatest part of my career working on the margins of the field – at a South African University – I have seen how the ripples of Castle's work often washes over (or even washes away) the kind of fine grained, highly localized and contextual research undertaken on these margins. Conceptually, the focus on class, formal labour regimes, and particular forms of migration governance is important. However, it not only leads many to overlook the often informal economic and political processes that characterize migration in the global south, but it means those focusing on such spaces and process still remain somewhat outside recognition within the field. The strong emphasis on class-based analysis, for example, largely excludes societies which have not meaningfully differentiated along class lines or where class is only a secondary basis for political mobilization and representation. A premium on global theorizing, continued in the Age of Migration franchise, privileges those with the resources and scope for synthetic, aggregating work over those offering localized critique or contingent analysis. Where these appear, these examples are often framed as deviations or outliers rather than sites for global theorization. There may be equally or even more compelling reasons to consider the securitization of migration across Africa as part of global trends emerging through the interactions of aid, norms, and interests across regions. Missing these connections – either by treating the “South” on its own, or as a derivative of “Northern” processes, misses the chance to identify universal trends and patterns or to test universalized claims of “global” theory developed largely from a limited set of OECD cases. Given that migration is by definition multi-scalar, any pre-ordained or geographic boundary is ultimately unjustified. For example, as “Northern” states increasingly work beyond the law, or as forms of difference are negotiated in ever more diverse “host” communities, we may ultimately see that Africa has become the site in which to observe the West's future. Looking at the consequences for migrants alone also risks the contribution these processes of norm proliferation can make to theory. While we know that the majority of the world's refugees and migrants are located in the South, Southern-based scholars and even those working on processes that remain largely within the ‘south’ remain hard to find in the leading (i.e., most broadly cited) scholarly journals on the topic. It is, of course, unfair to blame Castles for the relative absence of “Southern” voices in framing the field or global debates on Migration Studies. There are instead a reflection on his legacy and the nature of migration studies more generally. In many ways these are not distinct to Migration Studies, but the particular normative framing and engaged scholarship that characterizes the field bring them into acute relief. Castles' legacy is manifold and will reverberate across space and time. It encompasses institutional, epistemological, ethical, and pedagogical contributions and advancements that leave few in the field untouched. The field itself is, after all, partially of his making. He remains a scholarly and political reference point for many, including me. Inspired by his ethical commitments to challenge inequality and ugly, oppressive practices, we must also seek to complement his work. We build on his legacy in efforts to realize a field that is ever more inclusive, critical, and global. It is a final testament to Castles that I have few doubts he would embrace this pursuit. The opinions expressed in this Commentary are those of the author and do not necessarily reflect the views of the Editors, Editorial Board, International Organization for Migration nor John Wiley & Sons.