Now in its second edition, presents a comprehensive introduction to radiogenic and stable isotope geochemistry. The first five chapters cover fundamentals including the physics of nuclei, radioactive decay, nucleosynthesis, geochronology, and the theory of stable isotope fractionation. The next chapter focuses on the isotope geochemistry of meteorites and their constraints on the formation of the solar system and the Earth. The subsequent three chapters cover radiogenic and stable isotope geochemistry evolution of the Earth’s mantle and crust. Three more chapters are devoted to the Earth’s surface, the exogene, including the hydrologic system, the biosphere, and climate. A new chapter in this edition focuses on the use of isotopes in paleontology and archeology. The final chapter is devoted to the isotope geochemistry of the noble gases. Illustrated in full color throughout, is intended primarily as a textbook for advanced undergraduate and graduate students. It is also intended as a reference for earth science professionals, reflecting the impact that isotope geochemistry has on virtually every aspect of the earth sciences, from climate change and geomorphology to geodynamics.