This book aims to open new fields of interest in phosphate chemistry and to suggest a new system of classification for phosphates. Due to the very rapid development of this branch of chemistry during the last thirty years and the very confusing nomenclature often used in chemical literature, this first attempt seems not only justified but necessary. The suggested classification is not revolutionary, with respect to condensed phosphates for instance, but establishes clear boundaries between some categories of compounds such as adducts and heteropolyanion-compounds. The first chapters cover the present state of phosphate chemistry in a general way and could serve as an introduction to phosphates for some categories of students or teachers. The next few chapters are devoted to more specialized topics which would be of interest to chemists, crystallographers or solid-state specialists.Some specific aspects of the crystal chemistry of phosphates, such as the geometry of the networks built by acidic phosphoric anions, for instance, are covered for the first time. The final chapter suggests some improvements for the present system of classification for phosphates.In addition, presented for the first time are the results recently obtained for the replacement of asbestos by harmless biodegradable phosphate fibers.