Cosmology: A Very Short Introductionexplains what cosmology is and what cosmologists do, looks at the history of the subject, the development of the Big Bang theory, and more speculative modern issues such as quantum cosmology, superstrings, and dark matter. The subject matter of cosmology is everything that exists. The whole system of things that is the Universe encompasses the very large and the very small, the astronomical scale of stars and galaxies and the microscopic world of elementary particles. Between the two lives a complex hierarchy of structure and pattern that comes from the interplay of forces and matter. The aim of cosmology is to place all known physical phenomena within a single coherent framework.