" It's almost as if Kennedy grabbed a decade out of the 21st century," Cernan said, " and spliced it into the 1960s." That helps to explain why, as I wrote in 1993 in the preface of this book, we weren't entirely ready for Apollo, and why we have struggled to absorb its impact ever since it happened. How could the most futuristic thing humans have ever done be so far in the past? "