If you want to acquire a solid foundation in RFID technologies and your goal is to prepare for the exam, this book is for you. You'll find clear explanations of the concepts you need to grasp and plenty of help to achieve the high level of professional competency you need to succeed in your chosen field.
If you want to become certified as an RFID+ holder, this book is definitely what you need. However, if you just want to attempt to pass the exam without really understanding RFID, this Study Guide isn't for you. It's written for people who want to acquire hands-on skills and in-depth knowledge.
In addition to reading the book, you might consider downloading and reading the white papers on RFID that are scattered throughout the Internet.