The idea of uncertainty forms a major theme throughout the essays collected here; they tackle aspects of religious, intellectual, political and social history, highlighting how uncertainty, in many and varied forms, was conceptualized, negotiated and exploited in the particular conditions of the long thirteenth century. A number of the contributions explore understandings of the cosmos and personal salvation, probing the search for certainties on the partof ecclesiastical reformers, practitioners of scriptural exegesis and writers of confessional handbooks; there is also an investigation of the exploitation of ambiguities around the fate of excommunicates. Other pieces turn to politics and society, examining strategies of political legitimation and resistance, the unstable politics of identity, gendered experience and means used to regulate social order. As a whole, the collection thus opens up diverse perspectives on, and approaches to, the experience of uncertainty during a period of rapid and often disorienting change. Andrew M. Spencer is an Affiliated Lecturer in Medieval History at Cambridge University and a Fellowof Murray Edwards College; Carl Watkins is University Senior Lecturer in Central Medieval History at Cambridge University. Contributors: Emily Corran, Kenneth Duggan, Lucy Hennings, Felicity Hill, Adrian Jobson, Frédérique Lachaud, Amanda Power, Jessica Nelson, Andrew Spencer, Alice Taylor,