Dave Perry is an expert at the racing rules and a talented teacher. There are certainly other ways to learn the rules, but none is as lighthearted or as complete.
As a part of this book you get a copy of the complete official version of the rules as well as Dave's easy to follow structure and "questions and answers" sections. I suggest that you read this book in short sessions, taking the time to visualize what is being talked about (easy to do given Brad Dellenbaugh's great illustrations.)
The reason to read other rules books is to review the rules once you've learned them with Dave Perry. And if you're like many people, when his new version comes out in four years (the rules are tweaked every Olympic year) you will order a new copy and be reminded how easy he makes it to learn the rules.