Some of the ideas developed and defended in this book originated in my doctoral thesis, 'Adjudication and Discretion', submitted at Oxford University. I am delighted once again to acknowledge my overwhelming debt to Herbert Hart who supervised the thesis and provided me with the kind of guidance and encouragement of which doctoral students' dreams are made. Professor Hart has continued to offer his insightful comments on my written work, and for his ongoing assistance and generosity I am extremely grateful.
During the past decade I have incurred several other debts of gratitude. Many friends and colleagues commented on drafts of essays in which my ideas were being developed. These include Dick Bronaugh, who first introduced me to legal philosophy; Steven Dehaven; Ronald Dworkin, who despite his almost complete disagreement with my ideas has on several occasions offered an encouraging word; Chris Gray; Les Green, with whom I have had many fruitful conversations on the issues addressed in this book and who commented on drafts of several sections of the book; R. M. Hare; Michael Hartney; Barry Hoffmaster; John King-Farlow; Ken Lloyd, my first graduate student in legal philosophy, from whom I learned at least as much as he learned from me; Neil MacCormick, who along with John Mackie served as examiner of my doctoral thesis and offered many helpful suggestions; Joe Murray; Spiro Panagiotou, who helped me through some difficult times; Joseph Raz, who encouraged me to submit my manuscript to Clarendon Press and who provided many insightful comments on papers in which my ideas were being tested; and Roger Shiner, with whom I have had many discussions in legal philosophy and who taught me how to write a publishable paper. I also wish to thank my brother, Ted, whose encouragement and assistance were extremely beneficial. Finally, I wish to express my sincerest gratitude to Donna Farkas, whose support helped sustain me during the long process leading up to the completion of the manuscript. Without her warmth and inspiration this book would not have been completed.