Molecules in the early Universe acted as natural temperature regulators, keeping the primordial gas cool and, in turn, allowing galaxies and stars to be born. Even now, similarly simple chemistry controls a wide variety of the objects that populate our cosmos. What are the tools of the cosmic chemist? And what can they teach us about the Universe in which we live? These are the questions answered in this engaging and informative guide to The Chemically Controlled Cosmos.In clear, non-technical terms, involving no formal mathematics, we are introduced to a wealth of the most exciting astrophysics studied today, and the role of cosmic chemistry in the Universe.