The uplift of the Andes, beginning around 100 million years ago, profoundly reshaped regional climates and ecosystems across South America. This orogenic event created diverse habitats and a dramatic rain shadow effect, fostering biodiversity and endemism. Explorers like Charles Darwin and later naturalists laid the foundation for herpetological research in the region. Their pioneering work inspired generations of scientists to investigate the physiology, ecology, and evolution of Andean reptiles and amphibians. This book compiles studies from leading South American laboratories, highlighting adaptive strategies in extreme environments. It spans ecosystems from Colombia to Patagonia, including the Páramo, Puna, Yungas, and Patagonian Steppes. Four thematic sections explore biodiversity patterns, evolutionary histories, physiological adaptations, and conservation challenges. The integrative approach reveals how species respond to environmental pressures and anthropogenic threats. These insights deepen our understanding of montane life and underscore the urgency of preserving these fragile ecosystems. The volume serves as both a scientific resource and a call to action for future conservation efforts.