President Obama, the third sitting American president to win the Nobel Peace Prize, was selected from a so-called "short list" of 5 to 20 finalist candidates.

The Norwegian Nobel Committee's deadline for nominations was February 1, just 11 days after Obama's inauguration. Up to 200 nominations are received annually by the committee, a number that has risen steadily as the award has become increasingly global.

"There may occasionally be several thousand nominators behind one and the same nominee," the committee's Web site reads.

A record 205 nominations were received by the committee this year, including 33 organizations. The previous record was 199 in 2005.

A nomination is considered valid by the Nobel Foundation if it's submitted by a member of national assemblies and governments, including members of the Inter-Parliamentary Union; members of the Permanent Court of Arbitration at the Hague and of the International Court of Justice at the Hague; members of Institut de Droit International; university professors of history, political science, philosophy, law and theology; former Nobel Peace Prize winners and board members of institutions that have previously won; and former permanent advisers to the Norwegian Nobel Institute.

"The candidates on the short list are then considered by the Nobel Institute's permanent advisers," the site reads. "In addition to the Institute's Director and Research Director, the body of advisers generally consists of a small group of Norwegian university professors with broad expertise in subject areas with a bearing on the Peace Prize. The advisers usually have a couple of months in which to draw up their reports. Reports are also occasionally requested from other Norwegian and foreign experts."

In his will, Swedish industrialist and inventor Alfred Nobel said the Peace Prize, presented annually in Oslo, should be awarded "to the person who shall have done the most or the best work for fraternity between nations, for the abolition or reduction of standing armies and for the holding and promotion of peace congresses."

Obama, who was "humbled" by the award, according to administration officials, was praised for his "extraordinary efforts to strengthen international diplomacy and cooperation between peoples," the committee said.

Previous winners include U.S. presidents Theodore Roosevelt and Woodrow Wilson, former President Jimmy Carter, former Vice President Al Gore, Israeli President Shimon Peres, Palestinian leader Yasser Arafat and former U.S. Secretary of State Henry Kissinger.

Controversial nominees, meanwhile, have included Adolf Hitler, Soviet Union leader Joseph Stalin and Italian Prime Minister Benito Mussolini.

In 1956, the most recent year nominees for the award have been released, candidates included American Margaret Sanger, Spanish musician Pablo Casals and German Gertrude Baer for her work in the Women's International League for Peace and Freedom. No winner was eventually named, as was the case in 1955.

The committee does not release the names of nominees, and information in the nomination database is not made public until after a 50-year span -- so if you want to know who Obama beat for the award this year, check back in 2059.