Life holds one great but quite commonplace mystery. Though shared by each of us and known to all, seldom rates a second thought. That mystery, which most of us take for granted and never think twice about, is time. Calendars and clocks exist to measure time, but that signifies little because we all know that an hour can seem as eternity or pass in a flash, according to how we spend it. Time is life itself, and life resides in the human heart.