I actually bought 2 books about Sun bonnet. One is this book, and another is サンボンネットスーの12ヶ月120パターン.
Fist I don't know the difference, so why not, I buy both. THen, I found that this one is for beginners, there are step by step explanation. However, now so many photos and patterns. On the other hand, サンボンネットスーの12ヶ月120パターン has lots and lost of cute patterns, but not enough explanation of how to do. I guess it suits ones with experience.
So, if you are beginner, you may buy both and learn from the easier, then you can make one with more difficult but cuter.
If you have some experience, you may just skip this book and better buy サンボンネットスーの12ヶ月120パターン.