Perhaps no nation has been so thoroughly shaped by its dreams as has America, and perhaps no other dreams have been captured on camera as often and as diversely as America's.

The mythic American Dream has been the subject of photographic documentation since the 1840s, when photographers first began traveling to the New World in search of subjects. From an unknown photographer's picture of newborn George B. Billings Rego, scion of an immigrant Portuguese family and the first child ever born at Boston Long Wharf, to Lewis Hine's wrenching image of a young cotton mill worker in Georgia, to Alfred Stieglitz's awesome New York cityscapes, the photographs collected here reveal the multiple facets of 100 of the most decisive years of American development.

Between 1840 and 1940, immigrants became homeowners, untouched lands exploded in superhuman industrial growth, tourists replaced pioneers, and the American metropolis grew taller and shinier--and the camera caught it all.