He is regularly cited as one of the half-dozen or so most important thinkers of the last 50 years. After Virtue, published in 1981, is often listed among the most influential works of philosophy of the last century. Yet few who know his name and that of his most famous book could say much about who he is or why he matters.

First, he is a man of contrasts. Born in Glasgow in 1929, of Scots and Scots-Irish stock, Alasdair MacIntyre has written knowledgeably and proudly of the Scottish educational and philosophical traditions, but was raised, schooled and attended universities in England, and spent the first two decades of his academic career there before moving to the United States in 1970, where he has remained ever since.