In 1984 I sent a research proposal on migration to Harare to Professor Chris Mutambirwa, Head of the Geography Department of the University of Zimbabwe. He responded with interest. Thus began a research collaboration which has been central to the development of my ideas and understandings of migration and urbanization in sub-Saharan Africa. In the following year, when our first project was undertaken, and during subsequent rounds of surveys of migrants and their livelihoods, and on many other occasions when I was in Zimbabwe, the Geography Department hosted and supported me. The results of that research form the core of this book and the context from which I have developed my broader analysis of cities and circular migration in sub-Saharan Africa. I should like to thank everyone involved in the department. I am also grateful to all the research assistants and interviewees involved in our surveys over the years; special mention must go to Ruth Masaraure. Above all, I am indebted to Chris and his wife Jane for their support and affection for both me and my family over the decades since our first correspondence all those years ago. In the 1990s and 2000s, often with my young children in tow, I could not have conducted my work in Harare without the hospitality and friendship of Richard and Lynette Owen.