The authors in this volume discuss contemporary Islamic reformism in South Asia in some of its diverse historical orientations and geographical expressions, bringing us contemporary ethnographic perspectives against which to test claims about processes of reform and about trends such as ‘Islamism’ and ‘global Islam’. The very use of terminology and categories is itself fraught with the dangers of bringing together what is actually substantially different under the same banner. While our authors have often found it necessary, perhaps for the sake of comparison or to help orient readers, to take on terms such as ‘reformist’ or ‘Islamist’, they are not using these as terms which imply identity—or even connection—between the groups so named, nor are they reifying such categories. In using such terms as shorthand to help identify specific projects, we are following broad definitions here in which ‘Islamic modernism’ refers to projects of change aiming to re-order Muslims' lifeworlds and institutional structures in dialogue with those produced under Western modernity; ‘reformism’ refers to projects whose specific focus is the bringing into line of religious beliefs and practices with the core foundations of Islam, by avoiding and purging out innovation, accretion and the intrusion of ‘local custom’; and where ‘Islamism’ is a stronger position, which insists upon Islam as the heart of all institutions, practice and subjectivity—a privileging of Islam as the frame of reference by which to negotiate every issue of life; ‘orthodoxy’ is used according to its specific meaning in contexts in which individual authors work; the term may in some ethnographic locales refer to the orthodoxy of Islamist reform, while in others it is used to disparage those who do not heed the call for renewal and reform. ‘Reformism’ is particularly troublesome as a term, in that it covers broad trends stretching back at least 100 years, and encompassing a variety of positions which lay more or less stress upon specific aspects of processes of renewal; still, it is useful as a term in helping us to insist upon recognition of the differences between such projects and such contemporary obsessions as ‘political Islam’, ‘Islamic fundamentalism’ and so on. Authors here are generally following local usage in the ways in which they describe the movements discussed (thus, Kerala's Mujahid movement claims itself as part of a broader Islahi—renewal—trend and is identified here as ‘reformist’).2 But while broad terms are used, what the papers are actually involved in doing is addressing the issues of how specific groups deal with particular concerns. Thus, not, ‘What do reformists think about secular education?’, but, ‘What do Kerala's Mujahids in the 2000s think? How has this shifted from the position taken in the 1940s? How does it differ from the contemporary position of opposing groups? And how is it informed by the wider socio-political climate of Kerala?’ The papers here powerfully demonstrate the historical and geographical specificity of reform projects, whereas discourse structured through popular mainstream perspectives (such as ‘clash of civilizations’) ignores such embeddedness.