The purpose of this book is to define and describe the equity jurisdiction of the court of exchequer. It is to put this jurisdiction into its historical perspective and to provide aids and explanations for the use of whomever may wish to explore deeper into the subject or may wish to use the exchequer archives for other purposes.

In the first place I wish to express my gratitude to Mr D. E. C. Yale who suggested to me this topic of research and assisted me in my work for a doctoral dissertation on this subject. It is also my pleasure to express my gratitude to Professor G. R. Elton, Professor P. G. Stein, Mr M. J. Prichard, Dr J. H. Baker, Mr J. C. Sainty, and Mr T. A. M. Bishop, who helped me in many ways. Further acknowledgement is due to Clare College, Cambridge, who very generously supported me as a William Senior scholar during the last two years of my work on this subject. Also my thanks are due to the managers of the Maitland Memorial Fund and Christ's College, Cambridge, for meeting the expenses of my research in the first two years.

The staffs of the University Library Cambridge, the Public Record Office, the British Museum, the Bodleian Library Oxford, Lincoln's Inn, the Middle Temple, and the Inner Temple libraries have been unfailingly helpful, courteous, and long-suffering in regard to the problems of my research; I am grateful to them all.