precise, and optical atomic clocks that will provide time generation even ten times more stable. While it may not have seemed worthwhile to measure time by fractions of nanoseconds before the advent of modern day electronics, it is likely that pushing the boundaries once again will lead to technologies that are virtually unimaginable today. But for the time being, our quartz watches, accurate to half a second per day, will keep most of us on time for squash games, school plays and air flights. Just remember, when it comes to Daylight Saving Time: spring forward, and fall back!