The devastation caused by Hurricanes Katrina and Rita has made a best seller out of a book about an earlier American catastrophe. First published to critical acclaim in 1997, the book is called Rising Tide: The Great Mississippi Flood of 1927 and How it Changed America (Touchstone, Simon and Schuster). The author is John M. Barry, who is a scholar at Tulane University's Center for Bioenvironmental Research in New Orleans.

When Hurricane Katrina struck New Orleans, John Barry was in Washington, D.C., researching an upcoming book. As he watched the crisis unfold from a distance, he was struck by how it echoed events he'd described in Rising Tide.

The 1927 flood hit the lower Mississippi River region after an extended period of heavy rain, and Mr. Barry believes that until Hurricane Katrina, it was the most terrible natural disaster in American history. "In both cases," he says, "in advance of the disaster, people in New Orleans were shouting at the top of their lungs that we have a disaster waiting to happen, that the flood control policies the federal government is following are not going to work."

The two disasters were also similar in the amount of devastation they caused, says Mr. Barry. "Although most people today never heard of the 1927 flood, it actually put water in the homes of probably about 1% of the entire population of the United States. People died from Virginia to Oklahoma. And the greatest devastation was where it's hit today, in Mississippi and Louisiana. You had close to 700,000 people being fed by the Red Cross for months, some for more than a year, half of them living in tents, some for more than a year. So in terms of the scope, that was certainly similar."

But the author says that Hurricane Katrina is different in that it has damaged, or even destroyed, the reputations of so many politicians. He believes that in 1927 at least one political career got a huge boost. "Herbert Hoover was Secretary of Commerce, and he managed to put together rescue fleets of over a thousand vessels that picked up tens of thousands of people off rooftops and out of trees, and it created Hoover's Presidential candidacy and made him President of the United States."

The recent disaster also differed in that it was caused by a hurricane. But John Barry says there is an important link between the two events. "An unintended consequence of the 1927 flood was that on the lower Mississippi River from Illinois to the Gulf of Mexico, the federal government took total control over the flood control system and over the levee system, and they succeeded in preventing any floods since then on the lower Mississippi River. However, the river no longer dropped sediment because it no longer flooded, and that has contributed to the erosion of the marshland below New Orleans, which used to act as a buffer to hurricanes."

The coastal erosion was accelerated, Mr. Barry says, "when energy companies cut pipelines into the marsh. It let the saltwater directly into the marsh, so that today, a football field-size chunk of land in Louisiana melts into the ocean every 15 minutes. Ironically, just this year for the first time they got a substantial amount of money to start addressing that problem."

Issues of race have also been a theme in both events. "In 1927," says Mr. Barry, "blacks risked their lives to save whites. Whites risked their lives to save blacks. In the immediate aftermath, the race line almost disappeared. Over a period of time, however, when you have hundreds of thousands of refugees, most of whom were black, abuses began to develop in the refugee camps. And actually that, and the fact that people had lost everything, was a great spur for African American migration out of the South to Chicago, to Detroit, even to Los Angeles."

In the aftermath of Katrina, news headlines emphasized the fact that so many of the victims who seemed to suffer the most were black. But Mr. Barry does not believe that racial discrimination played a role in the delayed official response to the disaster.

"The Lower Ninth Ward of New Orleans is almost entirely black, but the neighboring community, St. Bernard Parish, is predominantly white," he says. "Both of these areas were the worst hit by the hurricane, and the first aid that the whites saw was not from the federal government or the state government, it was actually from the Canadian Mounties."

While the long-term impact of Hurricane Katrina has yet to be measured, John Barry says the most important legacy of the 1927 flood was a change in the way people viewed their government. "Before the 1927 flood, most Americans did not believe the government had any responsibility to help individual citizens. You were supposed to stand on your own two feet," he says. "But in 1927, a majority, for the first time, thought the federal government did have a responsibility towards individuals who were devastated and had lost everything."

Mr. Barry says, "that was a major shift that helped prepare the way for the New Deal. The question coming out of Katrina is whether we're going to see any kind of similar deep seated and widespread political response."

Looking back on the two disasters ---one nearly forgotten, the other still making news headlines -- John Barry believes there are common lessons to be learned.

"First, in 1927, the levying of the river helped create the vulnerability of New Orleans to hurricanes," he says. "That actually could have been avoided, and there are ways to let enough sediment out of the river to keep the marshlands vital. Also, don't cut canals through the marshland that let salt water intrude."

"People building major projects or developing new areas everywhere in the world are probably going to look a little more closely at the power of nature after what happened in Katrina," the author of Rising Tide says.

Mr. Barry also believes there are lessons the United States in particular should carefully consider. "We do not really have a national flood control policy," he says, "and when we do build flood protection, we build it for an event that's likely to occur once every 100 years. And the truth is, the extra money you might spend is not nearly as great as you might think. So you need to think about those things."