Perché la Chiesa, third volume of the trilogy PerCorso consists of two volumes.

In the first, titled La pretesa permane, the author analyzes “the crucial factors in the phenomenon of the Church as revealed by the documents that describe the emergence of Christianity in history” (Jaca Book, 1992, p. 9).

It develops and explores certain themes which the author had referred to in the early editions of the Senso religioso (GIAC, 1957, in the chapters “Dov’è ora Cristo” and “Chiesa: verità e vita”, pp. 22-32 and Jaca Book, 1966 in “Parte quarta. Presenza e storia”, pp. 75-92; reissue 1977, pp. 81-100). In 1965 and 1966 notes also circulated  titled Schema del corso della Chiesa (an account of encounters organized by the Charles Peguy Cultural Center in Milan) and for the academic year 1976-1977 a set of course notes was issued for students enrolled in the course of Introduction to Theology at the Università Cattolica in Milan, courses held by Father Giussani (Schema per un corso sulla Chiesa. Appunti presi a cura degli studenti, Cooperativa Universitaria Studio e Lavoro, pro manuscripto). These writings provide a compendium of his lectures and contain in brief what the other later developed in fuller detail in Perché la Chiesa.

In 1994 Jaca Book reissued the text in the first of two volumes that brings together the writings of Father Giussani under its imprint (Opere 1966-1992. Vol. 1. Il perCorso, pp. 329-467).

The work continued with the second volume titled Il segno efficace del divino nella storia (Jaca Book, 1992).

In 2001 the Cooperativa Editoriale Nuovo Mondo published the two texts in a single volume, after the Jaca Book edition was sold out, so permitting its use in courses in higher educational institutions and universities.

In 2003 Perché la Chiesa received its definitive format in the Rizzoli edition of PerCorso (1997-2003).