I am indebted to the staff of many libraries: University Library, Medical Library, African Studies Centre Library, and St John's College Library, Cambridge; London School of Hygiene and Tropical Medicine; School of Oriental and African Studies, London; British Library for Development Studies, Falmer; British Library, London and Boston Spa; Library of Congress, Washington; South African National Library, Pretoria and Cape Town; University of Cape Town Library; Cullen Library, University of the Witwatersrand; Ministry of Health, Entebbe; Makerere University Library; Albert Cook Memorial Library, Kampala; Medical Library, Kenyatta National Hospital, Nairobi; and Medical Library, Muhimbili Medical Centre, Dares Salaam.

Among individuals I am especially grateful to Shane Doyle, Pieter Fourie, John Lonsdale, Margie Struthers, David Throup, and Megan Vaughan. James Currey Publishers deserve my thanks for the urgency with which they have undertaken publication.

Writing the book has left me with profound respect for the epidemiologists and medical scientists on whose work it draws. If, through ignorance or hubris, I have misrepresented any of their findings, I apologise in advance.