On February 10, 2007, Barack Obama stood before the Illinois capital building and announced his potentially historic presidential bid. The next day, he was in Iowa Falls, campaigning. He was far from the first-Hillary Rodham Clinton, John Edwards, John McCain, and Mitt Romney were already swarming the Hawkeye State, seeking votes behind every hay bale. Why Iowa? After all, in the lead-up to the 2008 presidential primary, both Iowa and New Hampshire have come under significant fire-as usual. Critics like Sen. Carl Levin (D-Mich.) have charged that these early contests dominate the nomination process, yet are badly out of step with the ideology and demographics of the party and the country writ large. However, while New Hampshire has suffered a serious setback, Iowa has once again emerged as the first presidential primary contest, in part by arguing that its Precinct Caucus was a time-honored tradition that helped winnow the field with good old retail politicking and grassroots activism. This debate comes to a head this coming Winter, when tens of thousands of Iowans will troop to libraries and churches, prepared for an hour or more of party business. Each of these party meetings, or caucuses, will hold straw polls, the results of which will be broadcast around the world. One analysis found that the Caucus generates 143 times as much media coverage as other presidential primary contests, controlling for the date and size of the contest. In other words, being first thrusts the Iowa Caucus onto a towering public stage with extraordinary public interest. Both of these factors-the normative public debate and the empirical public frenzy-demonstrate the need for a very close look at the Caucus, in all its warts and beauty. Grassroots Rules was written to provide just such a study.