I wish to record my particular thanks to Professor F. A. Hayek, who first aroused my interest in John Stuart Mill. Since I assisted him during the war years in tracing original material about Mill, the world of my imagination has been peopled by Mill and his circle of friends.
I desire to thank the Librarian of the British Library of Political and Economic Science for permission to quote from unpublished material in their possession.
My sincere gratitude is due to Mrs. M. Binns for preparing the index and for her painstaking editing and correction of proofs.
Last, I should like to express my appreciation of those friends who contributed to the completion of the book by affording me relief in my care of family, house, and garden: Miss M. Zils, Mrs. E. Gardiner, and Mr. D. A. Smith.