Perché la Chiesa. Il segno efficace del divino nella storia is the last section of PerCorso.

In this work the author dealt with the issue of the Church starting from “what the Church claims to be” and from the “awareness that the Church has of itself” (“Introduzione”, Jaca Book, 1992, p. 9).

It develops and explores certain themes the author had referred to in his first publications on the Senso religioso (GIAC, 1957, in the chapters “Dov’è ora Cristo” and “Chiesa: verità e vita”, pp. 22-32 e Jaca Book, 1966, and in “Parte quarta. Presenza e storia”, pp. 75-92; reissued 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, 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. 469-617).

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).