The Iowa Caucus slated for Thursday will formally kick off the 2008 U.S. presidential election.
The following is a series of events leading up to the race.
The whole process roughly started in November 2006, when potential candidates formed exploratory committees or announced their candidacies.
In 2007, candidates campaigning moved forward at full speed and some candidates dropped out due to fierce competition.
Among phases of the presidential race, the nomination contest from January through June and the Nov. 4 presidential election are the most important ones.
In the nomination contest, the Republican and Democratic parties will each determine their candidate for presidency based on a series of state-by-state primary elections, including caucuses and primaries.
The Jan. 3 Iowa caucus and the Jan. 8 New Hampshire primary are the first two major events in the nomination process, serving as the winnowers or vanes for the fate of the candidates.
The next big event is the so-called "Super Tuesday" of Feb. 5, when primary elections will be held in 22 states, including New York and California, whose combined population accounts for half of the United States.
By that time, since most states will have held primary elections, the nomination race will largely be settled.
There will still be some sporadic primary elections through June, but they will exert no big impact on the final result.
The two parties will each hold a convention by the end of the summer, formally announcing respective candidates for president and vice president and their policy platforms.
On Nov. 4, all 50 states and the District of Columbia will hold elections to select members of the Electoral College and the winner of the 2008 U.S. presidential race will emerge that night.