The document below was a presentation by the USGA to the PGA tour pros to explain how thw World handicapping System will work. It is largely illustrative (rather than all text) and provides an excellent explanation of how the World Handicap System actually works and calculates the changes required to handicaps. Whilst not a '2-page summary' it is easy to follow and, whilst it is not essential for all golfers to understand this level of detail, it is an interesting read and worth flipping through the slide pages. 

Note: it is quite a large file and may take a little time to load with slower broadband speeds.