The men have one thing in common: They are professors of the privy.

You know, the outhouse: the close stool, the temple of ease, the jakes, the bog-shop, the garde-robe, or, as it was most often called in early America, the necessary.

Everyone used them. But our ancestors showed an understandable reluctance to leave a lot of information behind about how they worked. Except for the occasional Renaissance engraving depicting a housewife dumping the contents of a chamber pot into the street, or the rare poem by John Gay celebrating Cloacina -- the Roman goddess of the sewer -- what used to go on in the privy has remained private.

Until now. Michael Olmert, an English professor at the University of Maryland at College Park, and Kent Mountford, an environmental historian in Lusby who is known for his study of roadkill, are telling the story of the necessary, one temple at a time, at lectures and in magazine articles.

The two men don't even know each other. Olmert has a long-standing interest in Colonial architecture, and Mountford is fascinated with the effect of outhouses on the environment. But each hopes that the tale of the outhouse will shed light on life in ante-bathroom America.

The privies are a gold mine, historically speaking. People would accidentally drop items -- coins, pipes, medicine bottles -- into toilets, and they have been reclaimed by future generations trying to understand the past.

The subject drew three dozen students of the stall to Olmert's lecture, held recently on a blustery night at the visitors center at the archaeological site in London Town, a long-vanished village south of Annapolis. The attendees were a varied lot. Children scampered through the aisles while slides were prepared. Several of Olmert's college students dropped by. And women outnumbered men, disproving the old assertion that only those with a Y chromosome have an interest in bodily functions.

Olmert, dressed in the professorial uniform of navy blue sweater and tie, dove into his talk with barely a hint of irony. "It's really hard to make a lecture about outhouses without a lot of wink-wink," he acknowledged. "But it really is a serious business."

With the lights down, the audience learned quickly that sanitation was a grim affair in the Colonial period, an era renowned for the elegance of its architecture and refinement of its manners. Waste management was an activity that took place under cover of darkness, conducted by well-paid "night soil" men, who had the unappetizing job of taking waste outside the city to be used as fertilizer.

"We know that some of the same carts used to take away waste at night were used to bring in vegetables in the day," Olmert offered as a piece of troubling trivia.

The crowd cried in disgust. "Sorry," Olmert said. There was no evidence of the practice in America, he added. That was a British thing.

At times, the crowd seemed to share Olmert's almost giddy fascination with the architecture of the old outhouses, which he reviewed in dozens of slides from estates in Maryland and Virginia. The outhouses usually were octagonal and even made of brick at the finest estates, monuments to the prestige of such owners as George Washington and Thomas Jefferson.

"It's like a little temple!" Olmert exclaimed after coming upon the slide of one particularly well-appointed privy that had steps leading up to the entrance. "What a great house," he gushed. "What a great place to go to the bathroom."

The privies often had more than one seat -- a throne for the paterfamilias and smaller ones for the wife and children -- leading Olmert to theorize that going to the bathroom was a social activity. (Partitions between stalls are a 20th-century development.) "Things like that didn't bother them," Olmert observed.

Mountford, who was a scientist at the Environmental Protection Agency until he retired recently, had a different motive for starting his hunt for outhouses: He learned that modern septic systems didn't dispose of nitrogen efficiently, allowing dangerous amounts of it to seep into the Chesapeake Bay and aquifers.

"I began to think, outhouses, are they so bad?" Mountford said. They took up less space and required less infrastructure, and they used no water.

Mountford has tried to bring the history of the privy into the modern era. "I brake for outhouses," he told another group of about 30 people gathered in the Maryland Department of Natural Resources building the day after Olmert's lecture. He has amassed a collection of thousands of pictures of privies still standing in Maryland and says he hopes to create a calendar called "Chesapeake Outhouses of the Month."

The product might be of interest to some of the estimated 10,000 Marylanders who still use outhouses. Some use the privy's modern successor, the composting toilet, which also requires no water and transforms the waste into more hygienic fertilizer. Composting toilets are even a feature at the Chesapeake Bay Foundation's education center.

"The dirty secret there is that the staff of the education center uses real toilets, and guests use the composting [toilet]," Mountford noted.

Mountford admitted he wants to build a temple of his own someday, as soon as his wife will allow it.

Until then, he'll be going to that other place, the toilet: you know, the commode, the potty, the head, the porcelain god. The place where some people even read the newspaper.

The crescent shape carved on the door of this outhouse on Hooper Island in the Chesapeake Bay, near Maryland's Eastern Shore, signifies that it was to be used only by women.Privies with lengthier histories than this 25-year-old outhouse on Hooper Island can provide details about bygone cultures.Outhouses like this one on Taylor's Island in Chesapeake Bay, could become alternatives to modern septic systems that allow dangerous amounts of nitrogen to seep into the bay, a Maryland scientist says.