Many different types of books have value. Some, like encyclopedias, are broad works which give general introductory material. Such books help people learn if they are really interested in something and need to get a basic idea of what is involved.
Then there are also in-depth resources that reveal intricate and detailed information. Sometimes this type of resource will contain lots of interesting bits of information, but have no continuity.
Breaking the mold of the latter is Edain McCoy's wonderful book, The Sabbats. This is one of the most in-depth studies of the eight major Pagan holidays ever written. In it you will discover the history of the eight holidays — Samhain, Mabon, and the rest. But that is not all. You'll also learn ways to celebrate the festivals including games, arts and crafts, music, recipes for traditional foods, and much more.
I suspect that you will read this book twice. First, it is such fun that you are going to read right through it, learning all about the holidays you celebrate. You'll learn their sources and alternate methods of participating in the festivals. This alone will add greatly to your understanding of the Wheel of the Year.
But second, you're going to pull this book out and go through it every time a Sabbat is about to occur. You'll look at it for new ideas and deeper understandings of the day. Of course, you might also want to use the glossary of common Pagan terms on a daily basis, so don't put this book on a back shelf!
This is a book you will learn from initially, and then learn more from every time you open its fun and intriguing pages. This book must be on your shelf.