Developments in Geochemistry, Volume 3: Helium Isotopes in Nature presents the isotopic investigations of noble gases. This book describes the origin, the history, and the contemporary distribution of isotopes of helium. Organized into 11 chapters, this volume begins with an overview of mass-spectrometric methods and measurements of the helium isotope abundance. This text then discusses the methods of collecting various terrestrial samples as well as the apparatus for helium extraction, volumetric measurements, and purification. Other chapters consider the isotope composition of primordial, radiogenic, and spallogenic light noble gases. This book discusses as well the origin and distribution of helium isotopes in meteorites, in the Earth's mantle, the crust and ocean, and in the atmosphere. The final chapter deals with the scientific and applied problems that can be resolved to the progress in helium isotope geochemistry. This book is a valuable resource for scientists. Research workers and students interested in the geochemistry of helium will also find this book useful.