This book is devoted to the study of cryohydrology in hydrological research in cold regions through theoretical aspects, field observations, remote sensing and GIS, hydrological model, and impacts on regional and global scales. Understanding cryohydrology is a prerequisite to the hydrological processes in cold regions. The book aims to serve as a guide for understanding and developing cryohydrology by observation and modeling. It is motivated by recent rapid advances in cryospheric science including the discipline trees, in addition to the impact of cryospheric changes on different scales. Chapters are carefully developed to cover (1)development of cryohydrology, (2) research methods, (3) ablation, runoff generation and routing, (4) meltwater runoff, (5) hydrochemistry, (6) river sediment, (7) roles in watershed, and (8) impact on global water cycle. It addresses the above issues with a holistic and systematic approach that utilizes observation to simulation. The book is written for scholars working in hydrological research fields as well as stakeholders engaging in environmental sustainability in cold regions.