Students began trickling in early. Some dressed up in button-down shirts. Nervous chatter and fidgeting arose around the room.
And then in walked Professor Ben Bernanke, also known as the chairman of the Federal Reserve.
The 30 undergraduates at George Washington University sent up a round of applause. It was, they'd been told beforehand, "appropriate, even encouraged, to politely applaud" Tuesday's guest lecturer.
Few needed prompting. They were about to hear from perhaps the world's best-qualified person to lecture their class, titled "Reflections on the Federal Reserve and Its Place in Today's Economy."
"We have a chance to speak one-on-one with a guy who's arguably one of the most important people in the world," said Sameer Iqbal, a junior finance major from Potomac, Md.
"He's taking time out of his schedule to speak to 30 college kids? I think that's awesome."
Also, unusual. In giving the first of his four scheduled lectures to the GW class, Bernanke became the first sitting Fed chairman ever to help teach a college course.
Reporters and news photographers nearly matched the number of students. Bags were searched. And security personnel stood guard.
Michael Feinberg, a senior finance major, said he normally doesn't get to class a half-hour early. But "normally I don't have my bag sniffed by a bomb-sniffing dog."
Wade Harris, a junior finance major from Melbourne, Fla., made sure to wear a tie under his sweater.
"Opportunities like this are one of the main reasons why people come to GW," he said. "Regardless of what your major is, it's relevant to the world we live in."
Tuesday's lecture focused on U.S. central banking dating to the panics of the 19th century and early 20th century, which led to the Fed's creation in 1913. The second lecture, on Thursday, will involve the central bank's actions after World War II.
In the final two, on March 27 and 29, Bernanke will review the roots of the 2008 financial crisis and the Fed's response to the crisis and the recession that followed.
Anyone can view Bernanke's lectures live (at http://www.ustream.tv/channel/federalreserve). The Fed will maintain the four one-hour lectures on its site for later viewing.
The number of people viewing Tuesday's lecture at the Fed's website held steady at about 3,300 throughout Bernanke's class.
The students seemed most engaged when the Fed chairman tried to convey macroeconomic concepts in real-world terms. He drew some laughs in describing the pitfalls of a gold standard for a nation's currency.
It is costly, Bernanke noted dryly, to dig gold up in "South Africa or somewhere" and "put back into another hole."
The lectures give the Fed chairman a chance to reprise the role of professor he played for more than two decades, first at Stanford and then at Princeton, where he eventually chaired the economics department.
He clearly enjoys that role. On Tuesday, Bernanke wasn't scheduled to field questions. Yet he stayed to do so, and he called on students by their first names, reading from the names plates in front of them.
Mostly, students listen intently to the lecture, which Bernanke delivered with the aid of a 50-slide PowerPoint presentation. The Fed chairman provided a tour through the history of central banking, beginning with the first central banks in Sweden, established in 1688.
Bernanke also reviewed the causes and the Fed's response to the Great Depression of the 1930s. During his years as a college professor, Bernanke was considered one of the country's leading experts on the Depression.
Some students acknowledged after class that they were a bit intimidated at first. But Bernanke put them at ease, they said, and they recognized the value of his insights.
"It's like taking basketball practice from Michael Jordan," said Dan Wright, a sophomore political science major from Cincinnati.
Bernanke's staff had approached GW late last year about the possibility of allowing Bernanke to give some lectures. The university and the Federal Reserve are within blocks of each other in the Foggy Bottom neighborhood of Washington.
GW assembled the class from 80 applicants who wrote essays on what they hoped to learn.
The GW lectures allow Bernanke a way to expand his mission of demystifying the Fed. As part of that campaign, Bernanke became the first Fed chief to hold regular news conferences and conduct town-hall meetings. The Fed this month also launched a Twitter channel _ (at)federalreserve.
Tim Fort, a business professor who specializes in ethics, developed the GW course in consultation with Bernanke's staff. Beyond Bernanke's lectures, Fort has enlisted about a dozen GW faculty members to help teach the class.
AP Economics Writer Derek Kravitz contributed to this report.