The Philosophy of John Stuart Mill demonstrates that Mill both saw his views as part of a systematic defense of empiricist epistemology and utilitarian ethics, and was to a large extent successful in offering a coherent and connected defense of this system. At the time Alan Ryan’s highly acclaimed study was first published, it was unusual in insisting on the systematic character of Mill’s philosophy. Since 1970, however, many writers have contributed to a more systematic understanding of Mill’s program for philosophy, ethics and social science, and Alan Ryan’s new preface to the second edition assesses the way Mill appears in this new climate of opinion.