What exactly is the so-called road map?
It is intended to be a goal-driven route to ending the Israeli and Palestinian conflict within two years. It is also meant to have specific target dates, benchmarks and reciprocal confidence-building measures built in.
The plan was pieced together by diplomats from the United States, Russia, the European Union and the United Nations, then amended after consultations with Israelis and Palestinians.
What are the main stages in the plan?
Phase 1 (to May 2003): End to Palestinian violence; Palestinian political reform; Israeli withdrawal and freeze on settlement expansion; Palestinian elections.
Phase 2 (June-December 2003): Creation of an independent Palestinian state; international conference and international monitoring of compliance with road map.
Phase 3 (2004-2005): Second international conference; permanent status agreement and end of conflict; agreement on final borders, Jerusalem, refugees and settlements; Arab states to agree to peace deals with Israel.
George Bush, the US president, has been less involved in the Middle East than many of his predecessors. Why is he now planning to meet leaders in the region?
The White House says the Middle East has reached a "hopeful moment" and the president wants to "do everything in his power to make it the most hopeful moment possible".
The president’s presence in the region could be seen as a reward to the Palestinians for appointing a new prime minister and to the Israelis for accepting the road map.
How important is US involvement in the process?
The US is the only country with sufficient leverage to get things moving. Other countries and mediators can make some progress, but the Israelis do not trust the European Union, Russia or the United Nations.
Is the road map likely to work when other peace initiatives have failed?
Optimists say this time, in a new Middle East after the war in Iraq, each side will face unprecedented pressure. Peace brokers believe this will force the two sides into concessions.
Pessimists say the fall of Saddam Hussein will not - in and of itself - have any effect. They also doubt the depth of Mr Bush’s commitment to the peace process.
Can Palestinian militants - especially suicide bombers - be reined in effectively?
The Palestinian prime minister, Mahmoud Abbas, has said the best way to rein them in is to negotiate a ceasefire with the armed groups. Many believe that is possible, but the militant group Hamas has denied that a ceasefire agreement is in the works.
Would the proposed Palestinian state be viable?
The road map explicitly aims to make it so. For the state to be viable, most accept that Israel would have to dismantle the majority of its West Bank settlements.
If the road map were implemented, how would it affect Israeli settlers and Palestinian refugees?
These are two of the most difficult areas of dispute. The road map delays final agreements on both issues until the end of the process. It calls for an initial freeze on settlement activity and dismantling of settlements built in the last two years.
Mr Sharon has commented that "painful concessions" would be needed for peace. Many observers interpreted that as a willingness to dismantle settlements.
The issue of refugees is also left to the end. The road map calls for "an agreed, just, fair and realistic solution" to the problem.