This chapter focuses on concerns that determine which kinds of knowledge are regarded as valid and useful under different circumstances. A thorough and critical literature review can constitute a point of departure for new projects and serve as the basis for the independent and innovative research that upcycles existing knowledge by finding new uses for and value in that knowledge. With the digital revolution and public accessibility to the internet in the 1990s, researchers all over the world could gain access to the international research literature with only a few keystrokes. Human experiences, values and priorities have a great impact on the priorities and emphasis placed on different sources of knowledge in general, in research specifically and in encounters with individuals. The chapter also presents an overview of the key concepts discussed in this book.