Relevance has been called the "What's In It For Me" (WIIFM) issue. If there is not something in the content that the learner really needs, then they normally do not want to be bothered with it. Relevance is learner driven, but must be teacher provided for optimal learning. Relevance is so important to the making of meaning that Eric Jensen (1996, 1997), a pioneer of brain-compatible learning, has defined relevance as one of the three critical factors to learner-constructed meaning. He says these three critical factors are Relevance, Emotion, and Context/Pattern. Learner-constructed meaning is synonymous with learning and with knowledge acquisition. This article discusses "The Twelve Principles for Brain-Based Learning" (Caine and Caine 1991, 1993), several of which are central to the importance of relevance to learning, and describes the implications of these principles for school library media specialists.