In December 1968, a picture of the Earth floating lonely in the dark expanse of space travels around the world. Taken by the Apollo 8 crew, the photo causes a social shock that never fully subsides until the moon landing on July 20, 1969. Footsteps on the Moon is the ultimate photochronic of NASA's space program, with more than 200 images from this eventful era taken with the large-format Hasselblad cameras.