Introducing the essentials of modern geochemistry for students across the Earth and environmental sciences, this new edition emphasises the general principles of this central discipline. Focusing on inorganic chemistry, Francis Albarède's refreshing approach is brought to topics that range from measuring geological time to the understanding of climate change. The author leads the student through the necessary mathematics to understand the quantitative aspects of the subject in an easily understandable manner. The early chapters cover the principles and methods of physics and chemistry that underlie geochemistry, to build the students' understanding of concepts such as isotopes, fractionation, and mixing. These are then applied across many of the environments on Earth, including the solid Earth, rivers, and climate, and then extended to processes on other planets. Three new chapters have been added - on stable isotopes, biogeochemistry, and environmental geochemistry. End-of-chapter student exercises, with solutions available online, are also included.