Membrane Hydration: A hint to a new model for bio membranes -- Use of X-ray and neutron scattering methods with volume measurements to determine lipid bilayer structure and number of water molecules/lipid -- Water and Lipid Bilayers -- Hydration forces between lipid bilayers - a theoretical overview and a look on methods exploring dehydration -- Monitoring membrane hydration with 2-(dimethylamino)-6-acylnaphtalenes fluorescent probes -- Long-Range Lipid-Water Interaction as Observed by ATR-FTIR Spectroscopy -- Hydration And Nano confined Water. Some Insights From Computer Simulations -- Aquaphotomics: near infrared spectroscopy and water states in biological systems -- Hydration in lipid monolayers: Correlation of water activity and surface pressure -- Water at Biological Phase Boundaries: Its Role in Interfacial activation of enzymes and metabolic pathways -- Anhydrobiosis: An Unsolved Problem With Applications in Human Welfare.