Fastest way to cramming on 19th & 20th Century European & American Art?

What is the best source to go to for cramming on 19th & 20th century European & American Art in general?
If there are areas within those aforementioned that can be overlooked to speed up the process, which are they? For now, just looking for a website and/or a book title or two that one could tackle in a few days of intense studying. Methodology suggestions are welcomed as well.