In the 19th century, the Scottish writer Thomas Carlyle famously wrote, "The history of the world is but the biography of great men", popularizing the "Great Man" theory that the course of history is shaped by a select few heroic individuals. While historians and others continue to debate the accuracy of the Great Man theory of history, there is no question that the course of history is permanently altered by decisive moments in time, where a different result would have produced drastically different outcomes. Charles River Editors' Decisive Moments in History examines the events that changed history forever and set the world down the path it finds itself on today.

Today the Space Race is widely viewed poignantly and fondly as a race to the Moon that culminated with Apollo 11 "winning" the Race for the United States. In fact, it encompassed a much broader range of competition between the Soviet Union and the United States that affected everything from military technology to successfully launching satellites that could land on Mars or orbit other planets in the Solar System. Moreover, the notion that America "won" the Space Race at the end of the 1960s overlooks just how competitive the Space Race actually was in launching people into orbit, as well as the major contributions the Space Race influenced in leading to today's International Space Station and continued space exploration.

Indeed, the Soviet Union had spent much of the 1950s leaving the United States in its dust (and rocket fuel). President Eisenhower and other Americans who could view Soviet rockets in the sky were justifiably worried that Soviet satellites in orbit could soon be spying on them, or, even worse, dropping nuclear bombs on them.