History is a collective enterprise, and one of my chief pleasures as an author is to express my appreciation to the many people who have contributed to this project. Professors Francesco Barbagallo and Paolo Frascani generously provided me with helpful advice on archives in Naples. Dr M. Soscia, Medical Director of the Cotugno Hospital, was a kind host, and he graciously assisted me in locating materials in the Hospital library and archive. The staffs at the National Library of Medicine at Bethesda, Maryland; the National Archives in Washington; the National Library at Naples; the Archive of the Bank of Naples; the State Archive at Naples; and the Sterling Library at Yale University provided endless and invaluable assistance in locating sources.

Colleagues at Royal Holloway, University of London and at Yale University have given helpful advice and support. Professors Henry Turner, Jr and John Harley Warner read the first draft of the manuscript, and made wise and valuable suggestions. The anonymous readers at Cambridge University Press offered helpful and informed criticism. Naturally, I alone am responsible for any errors that remain.

Research also requires financial support, and the Wellcome Trust made possible numerous field trips to Naples and to Washington, and enthusiastically encouraged my early research proposal. Sabbatical leave from Yale University and a grant from the Griswold Humanities Fund enabled me to bring the work to completion.

Most of all, however, I would like to express thanks to my wife, Judith. She was an inexhaustible source of enthusiasm, advice and humour. It is more than a rhetorical flourish to state that this book would not have appeared without her.