We have in these pages chronicled the feats of great explorers of previous eras. Yet our own era has witnessed what is perhaps the greatest, most awe-inspiring feat of exploration in the history of the man on earth: the Voyager program that made its way through the outer solar system. This was to be an exploration much different in kind from the great expeditions of old. There were no pack mules, native guides, or recalcitrant companions; but there were the same incredible risks of environment and circumstance that have accompanied exploration from the time the Phoenicians first circumnavigated Africa. The Voyager probes were man’s first tentative steps to walk beyond the confines of his own planet. Perhaps when the long perspective is finally taken by our remote descendants, the Voyager program will rank among the most the most significant event in the history of our species.