This book explores the mathematical foundations of range analysis, and its deployment in solving traditional power system operation problems in the presence of strong and correlated uncertainties. It addresses many relevant topics ranging from interval methods for uncertainty representation and management to various application examples. This book not only focuses on methodological breakthroughs and roadmaps in implementing the mathematical methodologies, but also presents the much needed sharing of best practices. The problems currently faced by possible readers are related to the sparsity of information on this topic, scattered between many self-consistent papers. The book links the knowledge accumulated on the topic in order to serve as a quick reference for practitioners.