A compelling adventure and an engrossing history, Through a Universe Darkly introduces the men and women who are peering into the celestial darkness, hoping to uncover the invisible substance whose discovery will unlock the secrets of the universe's composition and finally tell us how galaxies were born, how stars live and die, and whether our universe will end in a conflagration or limp outward to icy nothingness. Faced with the unknown, the world's first philosopher, the ancient Greek Thales, asked, "What is the universe composed of? " And thus started a centuries-long search that has led to the quarks and grand unified theories of modern-day physics. As celestial explorers have relentlessly stretched the boundaries of the star-spangled roof above us, this simple, rudimentary question of what it all is made of continues to perplex astronomers.