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, simple chemistries continue to control a wide variety of the exotic objects that populate our cosmos. What are the tools of the trade for the cosmic chemist and what can they teach us about the Universe in which we live? There are the questions answered in this engaging and informative guide to The Chemically Controlled Cosmos. In clear, non-technical terms, and without formal mathematics, we learn how to study and understand the behaviour of molecules in a host of astronomical situations. We examine the formation of stars deep within interstellar clouds, the origin of our own Solar System, the cataclysmic deaths of massive stars that explode as supernovae, and the hearts of active galactic nuclei, the most powerful objects in the Universe. We are given an accessible introduction to the wealth of astrophysics and an understanding of how cosmic chemistry allows the investigation of many of the most exciting questions concerning astronomers today.