Like ISAF is aknowliging with publishing Introductory Rules for Racing, for many beginner and young racers, the full text of the racing rules can be daunting.
If you participate in a race for the first time as a young sailor, you need help to understand them. After you've mastered the beginnings, there's an excellent book by Henk Plaatje (originally in Dutch, but now translated in English and German) to do that. Plaatje reduces the rules to their basic essentials and illustrates each with simple colour diagrams. The practical spiral binding and the water-resistant pages make the guide usable on board.
in Dutch: Regelschrift
in English: Yacht Racing Rules: The Essentials
in German: Tafeln Wettfahrtregeln 2005 - 2008
In the original Dutch book Plaatje uses the names of his daughters and wife for the boats..... Alas, that didn't survive in the translations....
If you do a little searching on the Internet with the titles you can find a good deal, because this is the last year they are applicable. No doubt that Henk Plaatje is working on an update for the next rule cycle.