(Undated) -- Daylight Saving Time ends this Sunday, but many Americans probably have no idea why they might be arriving to work an hour early on Monday.

[audio:PrerauDST11.mp3] [/audio]

Dr. David Prerau is the author of "Seize the Daylight," a book that delves deep into the strange and at-times contentious history of the event. Daylight Saving Time has actually varied in both location and the length of time for years. In fact, the current length of DST that the U.S. and Canada observes was only established in 2007, when legislators extended it by nearly an entire month in an effort to help conserve energy.

[audio:PrerauDST21.mp3] [/audio]

Dr. Prerau is the author of "Seize the Daylight," a book that delves deep into the strange and at-times contentious history of the event.