The formation and growth of black holes, the accelerating expansion of the universe, the echo of the big bang, the discovery of exoplanets, and the possibility of other universes—these are some of the puzzling cosmological topics of the early twenty-first century. Natarajan is an astrophysicist who literally creates maps of this invisible matter in the universe. She explores these discoveries that have reshaped our understanding of the universe over the past century, and takes us on a tour that will help make sense of our wondrous, mysterious cosmos.