 I owe thanks to Reuven Brandt, Aaron Cobb, Sam Clark, Fred Kroon, John Skorupski and Nick Unwin for reading drafts, offering comments, and correcting errors. As can be seen from the Bibliography above, I have learnt much about Mill during the process of co-editing A Companion to Mill—I therefore owe thanks to the contributors to that volume, as well as my co-editor, Dale Miller.