This wide-ranging text in isotope geology/geoscience allows students to integrate material taught in various courses into a unified picture of the earth sciences and gives a rational exposition of the principles used in the interpretation of isotopic data showing how such interpretations apply to the solution of geological problems. The book is current with references up to 1985, and chapters in this edition have been revised, and new chapters on Sm-Nd, Lu-Hf, Re-Os and K-Ca decay schemes and cosmogenic radionuclides have been added. Data summaries and references have been expanded, and problems for student study have also been included, along with line drawings with explanatory captions.