In their previous books, Hancock and Bauval made the case for the existence of a mysterious and as yet unidentified prehistoric "influence" evident in human culture, as seen in the monuments of Egypt's Giza plateau: the three Great Pyramids and the Great Sphinx.Here, they offer compelling evidence to suggest that for over thirty years, U.S. scientists with links to NASA have been involved in unpublicized expeditions to Giza. Their undeclared interest in the Giza monuments seems to coincide with research into the existence of curious pyramidal structures, and a gigantic Sphinx-like "face" that were photographed on the surface of Mars in the 1970s. Is a covert treasure hunt underway for a precious time-capsule from the distant past?