John Stuart Mill was one of the most important and influential philosophers of the nineteenth century. He was also someone who exemplified a view about the meaning of life that is widespread among both philosophers and non-academics: that projects are what make your life meaningful, and if a single project is large enough to occupy center stage in it, that is the meaning of your life. His brilliant career notwithstanding, Mill's life was a train wreck; the intellectual energy and philosophical ingenuity which he devoted to figuring out what had gone wrong make him a fascinating object lesson in the view that projects give life meaning. Elijah Millgram argues that what went wrong was the very fact that Mill's life was a project—the tragedy of his life was an almost inevitable consequence of living out this account of the meaning of life. At once a scholarly contribution to the history of an important philosophical figure and an intervention in an ongoing debate within moral philosophy, this book takes on a topic that people outside the academy expect philosophy to address, but which it too rarely does: namely, the meaning of life. It is simultaneously an exercise in biography and a novel reconstruction and reframing of some of the central theories and texts of the philosophical canon. Millgram's work attempts to look at the theory of rationality from an unusual angle by asking: what difference does it make to the shape and progress of someone's life whether he has one or another understanding of practical reasoning—that is, of how one ought to reason about what to do?