The chapter begins by addressing the question: Why do young children learn so quickly? The short answer is that they are learning names for objects and events they are experiencing directly. These words are concept labels and they are engaged in what we call meaningful learning. In contrast, school learning is too often rote learning where the concepts and principles children are learning are not related to direct experiences with objects and events. David Ausubel’s cognitive psychology was introduced in 1963 and we immediately applied this new psychology as the foundation for all of our future work. We rejected totally the behavioral psychology that had dominated the field of education for some one hundred years. We also rejected positivist epistemology in favor of the emerging constructivist epistemology. It was not until the late 1980s that cognitive psychology and constructivist epistemology became widely adopted.