Origins of critical social theory of emancipationCritical Social Theory (CST), in its broadest sense, is a transdisciplinary approach to the social sciences that applies critique to the status quo in order to emancipate humans and the planet from the negative consequences of modernity.A broad understanding of CST includes historical materialism, Frankfurt School theory, cultural theory, poststructural theory, feminist theory, and postcolonial theory (Manners 2018a, 322-3). For example, Craig Calhoun's seminal 1995 study of CST included engagements with Horkheimer, Adorno, and Habermas' Frankfurt School; Derrida and Foucault's postmodernism; Bourdieu's habitus, field, and capital; Haraway and Fraser's feminist theory; and hooks and Spivak's politics of identity and recognition.The transdisciplinary approach of CST demands the reorganisation of disciplinary practices in order to transgress and transcend pre-existing frames of knowledge organisation found in the social sciences and humanities, in particular history, sociology, economics, ecology, and politics. In this context, CST is an 'interpenetrating body of work which demands and produces critique … [that] depends on some manner of historical understanding and analysis' (Calhoun 1995, 35). This historically-grounded critique is essential because 'theory is always for someone and for some purpose' since 'theory constitutes as well as explains the questions it asks (and those it does not ask)' (Cox 1981, 128; Hoskyns 2004, 224). Scholarship and activism within CST is concerned with understanding how 'tradition', the 'status quo', and the 'mainstream' are self-perpetuating practices of modernity that have significantly negative consequences for humans, society, and the planet as a whole.As Max Horkheimer put it in 1937, these conditions necessitate a 'critical theory of society as it is, a theory dominated at every turn by a concern for reasonable conditions of life' (Horkheimer 1972(Horkheimer [1937. As discussed in the final section on imagining another Europe is possible, CST is different to the other critical theoretical approaches in setting out a holistic, ecological, and progressive approach to the planetary politics that characterise the 21st century.This contribution is a continuation and development of two decades of work on CSTs of European integration including 'unconventional explanations', 'critical perspectives', and 'dissident voices' that help make 'another theory ' and 'another Europe' possible (Manners and Whitman 2003;Manners 2007;Manners and Whitman 2016), building on the intellectual heritage