This is an introductory chapter and it introduces the Qinling Mountains as a pivotal geographic, ecological, and hydrological boundary in central China, highlighting their critical role as the nation’s central water tower. It outlines the unique significance of the northern Qinling region as a key source of water for the Guanzhong Plain. The chapter reviews past research on tectonics, biodiversity, hydroclimatology, and water resources, revealing both the richness of existing knowledge and persistent scientific gaps such as insufficient understanding of surface–groundwater interactions, climate impacts on water retention, and the ecological thresholds of anthropogenic stress. Drawing on results from recent field studies and national research projects, this chapter defines the objectives and structure of the book. Key questions to be addressed include hydrological dynamics, pollution risks, ecological sustainability, and integrated water resource strategies.