Subject is exactly Paul VI
Cardijn's third speech to the assembled bishops of Vatican II.
As a Council Father, Cardijn's submitted a written intervention on lay apostolate to Vatican II since discussion in the Council plenary was already complete.
As Paul VI prepared his first encyclical, Cardijn sent the pope as series of reflections on dialogue to aid in the drafting process.
The second part of Cardijn's reflections following his 1948 tour of Africa and Latin America.