Please find below references to books and articles explaining the current crisis in which Holy Mother Church finds herself. We start with the roots, the errors that gave rise to the crisis. Since doctrine is more fundamental than morals or practice, it is in doctrine that the roots are to be found. These roots are the principal errors of Vatican II: Religious Liberty, Collegiality and Ecumenism (which correspond to the three errors of the French Revolution: Liberty, Equality and Fraternity).
If you are new to Tradition and are looking for where to start, head on over to our Newcomer's Page.
Vatican II and the Crisis in General
Videos: SSPX FAQ Videos (these cover some topics below and are there also linked)
Podcast: Crisis in the Church series (SSPX Podcast)
Book: Catechism of the Crisis by Fr. Gaudron (Angelus Press)
Book: Open Letter to Confused Catholics by Archbishop Lefebvre (Angelus Press)
Book: A Layman's Guide to Vatican II by Arnaud de Lassus (Angelus Press)
Book: Time Bombs of the Second Vatican Council by Fr. Franz Schmidberger (Angelus)
Book: I Accuse the Council by Archbishop Lefebvre (Angelus Press)
Book: Iota Unum by Romano Amerio (Angelus Press)
Book: Cranmer's Godly Order by Michael Davies (Liturgical Revolution, vol. I)
Book: Pope John's Council by Michael Davies (Liturgical Revolution, vol. II)
Book: Pope Paul's New Mass by Michael Davies (Liturgical Revolution, vol. III)
Conference: In Defense of Tradition (2010 Angelus Press Conference)
Religious Liberty
Video: What is the Problem with Religious Liberty? (SSPX FAQ)
Book: Religious Liberty Questioned by Archbishop Lefebvre (Angelus Press)
Book: The 2nd Vatican Council and Religious Liberty by Davies (Angelus)
Encyclical: Mirari Vos by Pope Gregory XVI
Issue: Angelus Magazine, January/February 2013
Article: Religious Liberty (SSPX General House)
Article: Religious Liberty Contradicts Tradition
Article: A Question of Doctrine: Religious Liberty
Article: The Great Problem of Religious Liberty
Article: Toleration or Religious Liberty (Laisney)
Collegiality
Video: What is the Problem with Collegiality? (SSPX FAQ)
Article: A Study of Collegiality at the Second Vatican Council
Article: The Problem with Collegiality (Fr. Dominique Bourmaud)
Ecumenism
Video: What is the Problem with Modern Ecumenism (SSPX FAQ)
Book: From Ecumenism to Silent Apostasy by SSPX (Angelus Press)
Article: True vs. False Ecumenism
The New Mass
Video: What is the Novus Ordo Missae? (SSPX FAQ)
Conference: The Mass, Heart of the Church (2014 Angelus Press Conference) - especially Fr. Themann's conference.
Book: A Short Critical Study of the New Order of Mass (Angelus Press)
Book: The Mass of All Time by Archbishop Lefebvre (Angelus Press)
Book: Pope Paul's New Mass by Michael Davies (Liturgical Revolution, vol. III)
Book: The Roman Rite Destroyed by Michael Davies (Angelus)
Book: The Problem of the Liturgical Reform (Heavy lifting!)
Book: The Liturgical Movement by Fr. Bonneterre (Angelus Press)
Article: The New Mass, a Catholic or Protestant Mass?
Article: New Liturgy (SSPX General House)
Article: 62 Reasons Why We Cannot Attend the New Mass
Liberalism
Book: They Have Uncrowned Him by Archbishop Lefebvre (Angelus Press)
Book: The Liberal Illusion by Louis Veuillot (Angelus Press)
Article: What is Liberalism? (Fr. Peter Scott)
Encyclical: Libertas Praestantissimum by Pope Leo XIII
Modernism
Encyclical: Pascendi Dominici Gregis by Pope St. Pius X
Article: Pascendi Exposes Modernist Tactics
Book: 100 Years of Modernism by Fr. Dominique Bourmaud (Angelus Press)
Issue: Angelus Magazine, September/October 2020
Sedevacantism
Book: False Solution to a True Problem by SSPX Priests (Angelus Press)
Issue: Angelus Magazine, July/August 2017
Conference: The Papacy (2012 Angelus Press Conference)
Diocesan Latin Masses
(The question of FSSP, ICKSP, the motu proprio "Summorum Pontificum" and the "Indult Mass" are all in essence the same problem. They are treated in the resources listed below)
Article: Archbishop Lefebvre on the Indult Mass (passage from The Mass of All Time)
Article: The Pontifical Commission Ecclesia Dei Suppressed
Article: From Summorum Pontificum to Traditionis Custodes; from the Reserve to the Zoo
Sermon: Lefebvre on the Church, Priesthood and the Indult (see the very end)