A rapidly growing interdisciplinary field, astrochemistry is the study of molecules and their chemistry in sources throughout the universe. In IAU S231, astronomers and chemists survey the current state of the field. The contributions in astronomy show how the study of molecules has aided our understanding of the physical conditions in many different types of regions, from the interstellar medium of our own galaxy to the very edge of the Universe. The contributions in laboratory and theoretical chemistry show how much we have learned about these often exotic chemical processes and how much more there is to learn. Suitable for researchers and graduate students in diverse disciplines, this volume will provide a sense both of the scope of astrochemistry in the early years of the twenty-first century and the immense possibilities of this field for future growth.