This chapter presents the most important axes, foundations, and theoretical and conceptual frameworks for the entire book. It argues that, philosophically, neural therapy is ultimately grounded in complexity theory. Thus, we present the sciences of complexity and differentiate them from both complex thinking (i.e., E. Morin’s works) and systems science. Meaningfully, the vortex, so to speak, of the whole current scientific endeavor is based on quantum mechanics. This chapter digs into quantum biology, which allows to make clear that grasping health and life entails a highly counterintuitive approach. This contrasts with standard medicine, concerned basically with illness or disease. Furthermore, this introductory chapter studies a number of applications of complexity science to medicine. Four edges are highlighted here: biophotons and the new communication in the organism, the understanding of the brain and consciousness, thanks to quantum principles; the hypothesis of procaine for explaining the functioning of the brain; and the perspective of a nonlinear physiology.