This book has been long in the making. It began its life in 2010 as a collaborative research project on Islam and interfaith relations in northern Nigeria. Together with other members of the Nigeria Research Network, Raufu Mustapha and I undertook to map out the region's religious diversity and to study the ways in which the three main faiths – Christianity, Islam, and traditional spirituality – interact in what we have come to call Nigeria's religious encounter. As all the chapters demonstrate, this encounter has been varied and ever-shifting, involving violent confrontation as well as compromise and nonviolent competition, conversion, and cooperation between members of the different faiths. But over the last decades, it appears that violence has become more and more prominent, through riots, communal clashes, and even the full-blown insurgency of Boko Haram. The aim of this book is to explore northern Nigeria's religious encounter and suggest explanations for, as well as possible solutions to, the increasing violence that characterises it.

To my great sadness, Raufu passed away in the months leading up to the publication of this volume. As many have said, written and recognized, his passing is a great loss to all who knew him, as well as to the field of African studies and Nigerian politics in particular. Yet, at the same time, it is heartening and inspiring to recognize how many people have benefited from his guidance, advice and collaboration, and to realize the extent of the intellectual legacy he built through his publications, policy engagement, teaching, and supervision.

It is also very satisfying to see our volume finally going to press. As my doctoral supervisor and mentor, as well as colleague and friend, Raufu taught me much of what I know about Nigeria, Africa, and working in the academy. Perhaps unsurprisingly, the present volume touches on many of these lessons, of which I will highlight a few. Most importantly, the book aims to analyse Nigeria's religious encounter as it is, rather than as it is assumed or hypothesized to be. It aims to faithfully describe variation, nuance and complexity, acknowledging the many problems Nigerians face in their everyday lives, but also ensuring that we do not underappreciate the ways in which they creatively solve them.