Radiogenic and stable isotopes are used widely in the earth sciences to determine the ages of rocks, meteorites and archeological objects, and as tracers to understand geological and environmental processes. Isotope methods determine the age of the Earth, help reconstruct the climate of the past, and explain the formation of the chemical elements in the Universe. This textbook provides a comprehensive introduction to both radiogenic and stable isotope techniques. An understanding of the basic principles of isotope geology is important in a wide range of the sciences: geology, astronomy, paleontology, geophysics, climatology, archeology, and others. Written by one of the world's most respected and best-known geochemists, this full color textbook will be invaluable for all undergraduate and graduate courses on the topic, and is an excellent reference text for scientists. There are problems at the end of each chapter, with password-protected solutions available to instructors at www.cambridge.org/9780521862288.