Water in the proximity of a surface (interfacial water) is abundant on the earth. It is involved in various physical and chemical processes and crucial for biological function. Despite numerous studies of interfacial water, systematic analysis of its properties is missing in scientific literature. This book is a first comprehensive review of experimental and simulation studies of water in various confining environments, such as hydrophilic and hydrophobic surfaces, surfaces of biomolecules, porous media, etc. Systematic analysis of interfacial and confined water is based on the firm physical ground, which accounts for variety of the thermodynamic states of water near the surface, surface phase transitions, surface critical behaviour, effect of confinement on the bulk and surface phase transitions of water, clustering and formation of a spanning hydrogen-bonded water network via percolation transition. This allows distinguishing between universal features, common for all fluids, and some specific water properties, related to intermolecular hydrogen bonds. Special attention is paid to the properties of hydration water, which covers biomolecules and enables their biological activity. This book provides readers with basic information on interfacial and confined water, which will be useful for scientists and engineers working in the fields of bioscienses, nanociences and nanotechnologies.