In general terms, we could say that knowledge is produced through each individual’s perception of subjects. Thus, the study of knowledge, its concepts, its investigations, theories and terminologies, aims to determine the validity of this knowledge and the processes that allows us to obtain and access it. From the ancient Greeks to the present day, especially with the discoveries made by recent neuroscience researches, epistemological issues have been raising complex questions, which are still far from getting consensual answers. Considering this, this book introduces the reader to the Theory of Knowledge and argues on how advancements on this scientific field can be crucial for our understanding of the human mind and the social, political, economic and cultural aspects of the human society.