Once Before Time explores questions about the nature of time and space, and whether or not they have a definite beginning.Developments in physical theories (General Relativity, Quantum Mechanics, and attempts to combine them) have indicated that there is a deep connection between the history of the universe and the basic, microscopic nature of space and time, between the largest and the smallest scales.In this book, I provide an exposition of Loop Quantum Cosmology, a detailed framework that has highlighted this connection, and its supporting arguments. Readers will be stimulated to fathom an unexpected link—the interplay between the big bang’s discrete atoms of space and the fundamentals of space and time.The common myth of the big bang as the beginning of the universe and of time is based upon an illegitimate extrapolation of an incomplete theory.The expansion of the universe out of an extremely dense state is supported by General Relativity, but a prehistory of the universe is not accessible unless quantum physics is considered, too. Reconciling General Relativity and Quantum Mechanics is a formidable challenge. It is considered the “holy grail” of contemporary cosmology. This problem keeps a large fraction of theoretical physicists occupied. And while a comprehensive theory of the universe is not yet available; this book attempts to provide an abbreviated snapshot of the endeavor’s current status.