Mr. Fourth of July, the man behind the world's most voluminous all-Fourth Web site and soon an encyclopedia of the Fourth, never intended to devote a decade of his life to documenting the history, rituals and meaning of the nation's birthday.

But while working deep in the newspaper archives at the Library of Congress, James Heintze, a musicologist and librarian at American University, kept bumping into unusually detailed accounts of celebrations of the Fourth.

Before long, Heintze found himself spending countless hours documenting the musical selections of bands performing at Fourth celebrations, creating a detailed listing of each tune played throughout the 19th century. For many years, the Fourth was a time to premiere new music. Many early presidents were honored with marches composed in their names. "Hail to the Chief" was first played for a president, John Quincy Adams, on the Fourth in 1828.

"And then I realized you can't just pull out the musical events," says Heintze, who is AU's music librarian. "I had to tell the whole story."

If there's an aspect of the Fourth that Heintze has not examined, it'd take a heck of a researcher to find it. His site, gurukul.american.edu/heintze/fourth.htm, includes histories of Fourth speeches, prayers, fireworks, explosions, even dinners.

Heintze, who grew up in American University Park taking part in the usual neighborhood fireworks antics, has tracked the doings of every president on every Fourth, revealing that, for example, Jefferson was the first to throw a Fourth of July party at the White House, opening the doors to all District residents. Eisenhower spent seven of his eight Fourths at his farm in Gettysburg or at Camp David, in most cases playing golf, while Reagan was the last president to show much interest in Washington's fireworks, spending three of his Fourths watching the show here.

The holiday has changed with the history of the nation, becoming more subdued to reflect times of temperance, civil war or terrorism. The Oklahoma City bombing and 9/11 produced much quieter Fourths. But Heintze has found a consistent record of speechifying and celebration focusing on "liberty, pursuit of independence and the idea that we are the stewards of that for the next generation."

George Washington set the tone in 1778, when he had his troops in Princeton, N.J., stand in two rows and fire off their cannon in sequence, all the way down the line. Each man was given a double ration of rum to accompany the loud celebration of the nation's second birthday. That same year, "sky rockets" were fired in Philadelphia, launching another tradition.

In 1850, President Zachary Taylor demonstrated one of the chief dangers of the holiday by eating a bowl of cherries and milk that historians believe gave him the food poisoning that killed him five days later.

"People died in great numbers from food on the Fourth," Heintze says. "In one case, 100 people died from lemonade poisoning because it was served in copper tankards and the copper interacted with acid in the lemons."

The Civil War ended celebrations of the Fourth in the South for many years to come. As late as 1890, whites in Memphis marked the Fourth with a parade of men in Confederate uniforms.

The nation did not reunite in enjoyment of Independence Day until the Spanish-American War created a new wave of patriotism in 1898. "It took another war to clear the air for the South," Heintze says.

The revival led to a resurgence of the holiday's other great danger -- death and injury from wayward fireworks. The situation got so bad in the early 20th century that a national Safe and Sane fireworks campaign was born, leading many towns to stage official fireworks shows, aiming to lure the riffraff away from blowing up themselves and their neighbors.

In 1909, the District put on daytime fireworks in a vain effort to keep citizens off the streets. By 1926, the elements of today's Fourth were in place, with the Navy Band playing at the Sylvan Theater to accompany fireworks on the Mall.

Today, like most years, Heintze will head to the National Archives to watch reenactors play the Founding Fathers. He'll stick around for the parade. And he'll take in the fireworks. He couldn't do anything less.