Freed from public service, Mill turned to completing his life's work as an author: He brought out a revised edition of his father's Analysis of the Human Mind, which he had edited with the help of Bain and Grote back in 1867, partly as homage to his father and partly to shore up his case against Hamilton; put the finishing touches on his Autobiography ; edited the final editions of the Logic and the Principles of Political Economy; and prepared The Subjection of Women for publication in 1869.

What is remarkable about Mill's edition of his father's work is a series of footnotes in which Mill continued to distance himself from his father and to work out his aesthetic theory. Specifically, Mill criticized his father's account of associationism, for while it might be “a sufficient theory of what we may call the mental, or intellectual element of feelings … [it] does not furnish, nor does the author anywhere furnish, any theory of what may be called the animal element in them.” Moreover, Mill appealed to ideas he had found in the work of Ruskin to supplement his father's views. Mill had read John Ruskin's famous work Modern Painters, whose five volumes appeared between 1843 and 1860. Although he rejected Ruskin's political and religious conservatism, Mill found appealing the notion that art reflected both personal and national moral integrity.