This book is organized into five parts. Part One explores the origin, structure, and ultimate fate of the universe as a whole. Part Two examines the invisible components, dark matter and dark energy, that dominate the cosmos yet remain undetected directly. Part Three turns to the strangest individual objects in the universe: black holes, neutron stars, gamma-ray bursts, and gravitational waves. Part Four brings the focus closer to home, from the search for life to the unresolved questions still surrounding our own Moon, Mars, and solar system neighbors. Part Five considers the signals, real and hypothetical, that might one day answer whether we are alone. Each chapter can be read on its own, in any order, though reading front to back traces a rough arc from the largest scales of the cosmos down to the most immediate, human-scale questions about our place within it. Quick Fact boxes throughout offer a single striking figure or detail related to each chapter's topic, and two appendices at the end provide a glossary of key terms and a timeline of major discoveries for quick reference.
