The 90-minuted debate will be held at Hofstra University in Hempstead, N.Y. The candidates will sit face-to-face with moderator Bob Schieffer, a CBS news anchor.
Under such conditions, it will be hard for the candidates to avoid looking each other in the eye if and when they say negative things about each other or throw criticisms.
Tonight's topics, announced in September by the Commission on Presidential Debates, are critical to Obama's campaign as recent polls have shown him increasing in popularity as Americans try to decide who is better prepared to deal with the nation's financial crisis and economic downturn.
A New York Times/CBS News poll indicates that McCain has fallen as much as 14 points behind Obama - a lead that is also reflected in numerous battleground state polls.
Earlier this week, an ABC News/Washington Post poll showed Obama with a 10-point national lead.