This book is written by a leading authority on the subject of magmatic sulfide deposits. An overview of deposit types, accompanied by a summary of the resources of nickel, copper and platinum-group elements in the world's principal known deposits, is followed by a summary of the relevant physical chemistry. The core of the book comprises a discussion about the geology and geochemistry of each of the deposit types in turn, accompanied by the implications of this data to the origin of the deposits in the light of our understanding of the chemical processes involved. A final chapter focuses on the use of the genetic concepts in exploration.