Book excerpt: The book elucidates the role of inorganic polyphosphates in eukaryotic cells, from fungi and protozoa to human being. To date, there is plenty of evidence that these anionic biopolymers occurring in the cells of all living organisms, from bacteria to humans, perform numerous regulatory functions. The book describes the evolution of PolyPs, their role in lower eukaryotes and their involvement in various processes in the human organism, as well as its use in biomaterials such as bioactive glass and engineered bone tissue. The aim of this book is to summarize the data of the past decade on the functional role of inorganic polyphosphates in eukaryotes and discuss their biological role also in context of common human diseases. The book will provide a modern concept of the functional significance of these biopolymers, useful for researchers in cell biology, biochemistry, molecular biology and biomedicine alike.