Throughout the period during which this book has taken shape, I have received encouragement, support and help from many people. I should like to thank especially a number of my colleagues at Queen's University. Professor Christopher Crowder (my former supervisor) suggested Gerson to me as a subject of study, gently directed my research, and read, with an eagle eye, every version of the typescript. Dr James Stayer's graduate seminar on the Reformation introduced me to the historiography of late medieval theology, and Dr Stayer's friendly and patient criticism of my work has proved invaluable. Dr W. D. McCready and Dr P. Rogers both read an early version of the study and offered valuable suggestions and criticisms. Beyond the Queen's community, I received much encouragement and sound advice from Father Leonard Boyle, O.P. I should like to thank him and also the advisers to and the editor and sub-editor at Cambridge University Press for their helpful suggestions and assistance. Above all, I should like to thank my family for their patient tolerance and support during the years I have been engaged on this study, and especially my husband, whose willingness to discuss problems at length, to make suggestions and to proof-read has been of inestimable value.