In its profound teachings on marriage, the Second Vatican Council in 1965 stated precisely what difficulties husband and wife can face in relating their mutual love and the parenthood which naturally arises from expressions of that love. The Council reiterated the ancient and once universal Christian teaching that the morality of married intimacy depends on "preserving the full meaning of mutual giving and human procreation in a context of true love". It said that some questions about ways of regulating procreation were being studied by a commission (set up when the "pill" became available), so that the Pope could give his judgment on how God's law applies to those ways.

Humanae Vitae is Pope Paul VI's judgment, issued in 1968, applying the Council's teaching to those new questions, and later solemnly reaffirmed by Pope John Paul II and the Synod of Bishops. It is a momentous restatement of how love must, and must not, be expressed if it is to be marital love, true to the nature of human persons and of real marriage as a high and most significant calling.

In this 40th anniversary year of the encyclical, the CTS commissioned a new translation from the Latin text, with notes on some earlier translations, by John Finnis, Professor of Law and Legal Philosophy in the University of Oxford, Fellow of the British Academy, a member of the Pontifical Academy for Life and formerly of the Pontifical Council for Justice and Peace and of the Holy See's International Theological Commission.