Some of us may recall the story about the Chinese man who asked the world-record sprinter how he would make use of the extra hundredth of a second he won in the race. Although we often talk about using our time wisely or foolishly wasting it, time is hard to reify; after all, in a way, time itself is non-existent – instead we have a process, movement, and change. We can only conceptualize time by comparing it with something else. Time is most easily described by measurement: years determine age; weeks and months make up the calendar year; as a stretch of time, the brevity of a nanosecond is just as inconceivable as the length of a geological era such as the Cambrian Period. The way we assess human achievements bears some relation to chronology.