Water in itself is beautiful in terms of Structure, interactions (physiochemical, biochemical & chemical). In order to explore this beauty we have to study various models(Continuum model,Mixture models, Flickering Cluster Model & Frank – Wen flickering cluster model of liquid water) which are explained in a concise manner in this book. One must know the models and interactions because all scientists/researchers interact with water directly or indirectly during their research activities.