I’ve often encouraged a return and rereading of the writings of St John Paul II. He clearly saw and warned us of the situation we find ourselves in today. I would also suggest turning to Ratzinger when studying or trying to understand the effects of Vatican II. As a first person participant and observer his insights are deep and prophetic. This article is a good way to dig into Ratzingers writings along with many links to other articles. Don’t pass up the hyperlinks.
Source: Ratzinger Rising