More than 2,000 years ago, Eratosthenes, in Alexandria, used a stick, a hole in the ground, sunllght at summer solstice, and elementary geometry to measure the circumference of the Earth with surprising accuracy, long before anyone was able to circumnavigate it. Today, scientists are attempting to measure the entire universe and to determine its origin. Although the methods have changed, the quest to chart the horizons of space and time continues to be one of the great adventures of science.

Measuring the Universe is an eloquent chronicle of the men and women- from Aristarchus to Cassini, Sir Isaac Newton to Henrietta Leavitt and Stephen Hawking-who have gradually unlocked the mysteries of "how far" and in so doing have changed our ideas about the size and nature of the universe and our place in it. Kitty Ferguson reveals their methods to have been as inventive as their results were-and are-eye-opening. Advances such as Copernicus's revolutionary insights about the arrangement of the solar system, William Herschel's meticulous creation of the first three-dimensional map of the universe, and Edwin Hubble's astonishing discovery that the universe is expanding have by turns revolutionized our concept of the universe. Connecting centuries of breakthroughs with the political and cultural events surrounding them, Ferguson makes astronomy part of the sweep of history.

To measure the seemingly immeasurable, scientists have always pushed the boundaries of the imagination-today, for example, facing the paradox of an ever-expanding universe that doesn't appear to expand into anything. In Kitty Fergeson's skillfill hands, the unimaginable becomes accessible and the splendid quest something we all can share.