In a 1991 interview, Alasdair MacIntyre summarized the history of his own philosophical work as follows:

My life as an academic philosopher falls into three parts. The twenty-two years from 1949, when I became a graduate student of philosophy at Manchester University, until 1971 were a period, as it now appears retrospectively, of heterogeneous, badly organized, sometimes fragmented and often frustrating and messy enquiries, from which nonetheless in the end I learned a lot. From 1971, shortly after I emigrated to the United States, until 1977 was an interim period of sometimes painfully self-critical reflection⃜ From 1977 onwards I have been engaged in a single project to which After Virtue [1981], Whose Justice? Which Rationality? [1988], and Three Rival Versions of Moral Enquiry [1990] are central. The seven chapters that follow deal, for the most part, with aspects of MacIntyre's mature position, the theses that have emerged from the “single project” – I will call this, for shorthand, the “After Virtue project” – to which After Virtue, Whose Justice? Which Rationality?, Three Rival Versions of Moral Enquiry, and (since that interview) Dependent Rational Animals (1999) have contributed. My aim in this Introduction is to provide, albeit sketchily, some context for the emergence of MacIntyre's mature view. I want to say something, that is, about the pre–1971 inquiries that he labels “fragmented.” It is true that MacIntyre's writings during this period are remarkably diverse in the topics treated, in the styles employed, and in the fora in which they appeared. One does not find the singleness of purpose and the coherence of thought that mark his later work.