Catholic Marriage Prep

A reader writes:

I was just wondering if you or any of your readers knew of good books or websites for couples discerning marriage. There seems to be no shortage of books for engaged couples, but nothing I’ve really been able to find for pre-engaged discerning couples. Any help would be appreciated. Thanks and God Bless

I’m not much use on questions like this. Our parish uses and inventory called FOCCUS (which you can probably Google) and we help out with some of the marriage prep by going over the FOCCUS results with prospective couples, but beyond that I don’t have a very good knowledge of marriage prep literature. Maybe some readers could help?