The 40th-anniversary edition of Capitalism and Freedom contains three prefaces written by Friedman: the one that appeared in the first edition of the book; a second written, in 1982; and a third, added in 2002. The original notes how the book evolved out of a series of lectures he delivered at Wabash College in 1956. With great gratitude, Friedman notes the key role his wife, Rose, a fellow economist, played in creating the book. He also acknowledges the support he received from the University of Chicago, where he served as an economics professor.

Friedman starts the 1982 preface by sharing some of his key motivations for writing Capitalism and Freedom. He notes that:

[t]hose of us who were deeply concerned about the danger to freedom and prosperity from the growth of government, from the triumph of welfare-state and Keynesian ideas, were a small beleaguered minority regarded as eccentrics by the great majority of our fellow intellectuals (xi).

He also identifies a sizable shift in intellectual attitudes after Capitalism and Freedom was released, remarking that his follow-up book, Free to Choose, received much more national attention upon its release in 1980. He attributes much of this shift to 20th-century historical events. He says that by the time Free to Choose arrived, most people realized that Chinese communism and Russian socialism were fatally flawed, unlike in 1962.