The first of three debates (the other two are on Oct. 9 and Oct. 19), the showdown will be moderated by NBC News anchor Lester Holt, who is expected to divide the 90-minute session into three different topical segments: the Direction of America, Achieving Prosperity and Securing America.
The first ever televised presidential debate didn't happen until 1960. Candidates Richard Nixon and John F. Kennedy squared off -- just once -- in front of the camera, an event that proved extremely beneficial to the smoother and more youthful Kennedy, who went on to win the election against his stodgier opponent. It took another 16 years for the next presidential debate to happen. In the 1976 election, when President Gerald Ford faced off against his Democratic challenger Jimmy Carter, he made a notorious gaffe about the Soviet Union, an oversight that proved detrimental to his campaign.
Ever since, debates have become a fixture of U.S. presidential elections. It's now standard protocol for candidates to face off three times in the grueling months leading up to Election Day, providing Americans with a rare, unscripted glimpse of their personalities and how they handle themselves under pressure.
For more on the debate system and full-length videos and transcripts of past debates, visit Commission on Presidential Debates.