Start with the Introduction.

“It must be my turn.” George looked up at the Moon, closed his eyes, and began speaking, “The Moon is tidally locked to the Earth in its orbit. It circles the Earth and shows the same face to us with little variation. The side we don’t see, the so-called dark side, was first revealed to us in 1959 when the Soviet Union’s Luna 3 passed around the Moon and took photos. Unfortunately, the photos showed something that didn’t make any sense to the scientists who saw them. They assumed that they had seen some defect in the film and only released the images that made sense with their understanding of what was up there. The rest they discarded.