Below are some free digital books which give background material on Vatican II. They are all online versions of those books which have really stood the test of time.
This is a very cost-effective method of researching the crisis. If the book proves to be of particular value, then a new or second-hand version can be purchased.
Your device’s ‘search’ function (eg CTRL F) makes it easy to find keywords.
Clicking on the cover will take you to the free online version – they are all off-site.
Ecclesiastical Freemasonry 