I was not fortunate enough to know John Rawls personally. However, the interactions that I did have with him were consistent with what virtually everyone who knew him reports – he was generous, modest, and kind. Since our interactions were mostly professional – he was replying to my questions, commenting on papers and ideas – he was serious and focused and very helpful. I wrote to him for the first time soon after I read A Theory of Justice in graduate school. I am still amazed that he took the time to respond – as he did whenever I wrote to him over the subsequent years. He was a wonderful role model for a philosopher. It is to his memory that I dedicate this book.

A Theory of Justice was published in 1971. In early 1975 Rawls revised the text in preparation for the German translation. It was not until 1999, however, that this revised text was published in English. Rawls made no attempt to incorporate developments in his theory that occurred between 1975 and 1999 – in particular, he did not make revisions in light of the publication of Political Liberalism in 1993. Still, the revised edition includes some significant changes that Rawls regarded as improvements over the original text. It should be regarded as the authoritative text, and I quote from it accordingly.