Why is Clock Time so Important? On Time explores the changing ways we have measured, used, and thought about time over the past three hundred years.

1700–1820 Marking Time
Americans were deeply mindful of time, but not of the clock.

1820–1880 Mechanizing Time
Increasingly, Americans let the clock tell the time and regulate their lives.

1880–1920 Synchronizing Time
The country struggled to adjust to clocks set to a national standard time.

1920–1960 Saving Time
Americans became obsessed with using time efficiently.

1960–Today Expanding Time
We try to get more time out of every day.