Knowledge is at the core of what it is to be human, the substance which informs our thoughts and determines the course of our actions. Our growing focus on, and understanding of, knowledge and its consequent actions is changing our relationship with the world. Because knowledge determines the quality of every single decision we make, it is critical to learn about and understand what knowledge is. From a 21st century viewpoint, we explore a theory of knowledge that is both pragmatic and biological. Pragmatic in that it is based on taking effective action, and biological because it is created by humans via patterns of neuronal connections in the mind/brain. As humanity moves toward intelligent activity, knowledge, incomplete and imperfect, is the currency of our journey. The better our understanding of this human capacity, the greater the opportunity for making good choices. We begin by laying the foundation with clear definitions of information and knowledge, and levels and types of knowledge, then enter the realms of the voiced and unvoiced, delving into the dimensions of knowledge (explicit, implicit and tacit), engaging tacit knowledge and living through context. From a neuroscience perspective, we explore the magnificent mind/brain, social knowledge and the fallacy of knowledge reuse. Finally, we look at knowledge as values, moving from knowledge to wisdom, the relationship of knowledge and knowing, and sub-personalities as knowledge. We are in a continuous cycle of knowledge creation such that every moment offers the opportunity for the emergence of new and exciting ideas, all waiting to be put in service to an interconnected world. Learn more about this exciting human capacity!