NATO heads of state and government are scheduled to meet in Bucharest, Romania, Wednesday to Friday to discuss further enlargement of the alliance and key operations.
Traditionally, NATO did not hold summits on a regular basis. In recent years, a summit was held in every two years. A summit is being planned for 2009 to coincide with the alliance's 60th anniversary.
The NATO summit in November 2006 in the Latvian capital of Riga discussed NATO's operations in Afghanistan and the alliance's transformation.
It produced a Comprehensive Political Guidance, which saw terrorism and the spread of weapons of mass destruction as the main threats facing the alliance in the next decade.
The leaders invited Bosnia, Montenegro and Serbia to join a Partnership for Peace program.
Afghanistan was also a major topic in NATO's 2004 summit in Istanbul, Turkey. At the meeting, NATO leaders decided to expand the alliance's operation in Afghanistan and agreed to help the Iraqi interim government train its security forces.
They also adopted the Istanbul Cooperation Initiative aiming toforge closer ties between NATO and Middle Eastern countries.
The 2002 Prague summit invited seven countries to begin accession talks, which was a prelude to the biggest ever enlargement of the alliance in 2004. NATO leaders also decided to set up the NATO Response Force, a new concept force that is capable of various missions at short notice.
The 1999 Washington summit marked the 50th anniversary of the alliance. It made a key decision to intervene in Kosovo, a Serbian province, which was torn apart by a conflict between the Serbian authorities in Belgrade and ethnic Albanian separatists.
The Czech Republic, Hungary and Poland, which joined NATO on the eve of the Washington summit, also participated in the gathering.