The human rights to water and sanitation (HRtWS) have their genesis, history and interpretations. They are also subject to tension, controversy and dispute. A studied approach to these foundations is necessary in order to ensure a basis for their formulation, implementation, evaluation and monitoring. For the approach to the three dimensions that make up the analytical framework used in this book, an understanding of these aspects is not only desirable but necessary. Understanding the factors involved in the realization or violation of HRtWS, the ways in which the policies actually reach them, to a greater or lesser degree, and the population groups at particular risk, pre-supposes clarity regarding the different approaches for the rights and the elements that underlie each of these. In this context, the objective of this part of the book is to provide elements for the reader to get a closer view of these fundamentals, to get a more complete understanding of the topic and, from there, to have a theoretical-conceptual basis to address drivers, policies and people.