The Reading Booster B Books Set includes 20 adorable and fascinating books that correlate directly with the Reading Booster B Cards. The Reading Booster Cards will tell you when to read the Reading Booster Books. These books can be read as many times as desired for review and for cementing principles. Each book focuses on just one or a select few reading concepts, phonics principles, word families, or kindergarten sight word groups that were just learned on the corresponding Reading Booster Card. The books also only contain words including phonics principles the child has not already learned.