This unique survey describes the world's ancient phosphorite deposits on a scale never previously attempted. The International Geological Correlation Programme started Project 156, on world phosphate resources, in 1977. An international team of forty-six researchers describes in twenty-five chapters almost 100 Precambrian or Cambrian deposits of phosphate rock, extending through all continents except Antarctica. The total resources are large, but only a small fraction is minable at present. The data presented give a good understanding of the distribution, nature and origin of phosphate deposits. The book is an important contribution to the scientific understanding of phosphate deposits, as well as a valuable aid to the search for an exploitation of phosphates in many parts of the world.