In 1960, just as exam period was ending, a group of enterprising Harvard students put together a small pamphlet with tips for classmates who were about to begin a Harvard Student Agencies (HSA) charter tour of Europe.

Twenty-four years later and about 784 pages longer. Let's Go Europe has become the hottest selling budget travel guide in the country. More than 200,000 travelers bought one of last year's nine Let's Go guides, bringing gross sales to about $2.7 million.

But only about $165,000 of that total comes back to the HSA publishing office, which started off the series.

"We actually come up with losses most of the time," says Mark E. Fishbein '84, publishing manager. "It costs us a lot more [than a regular author] to put together a manuscript."

Most of the agency's budget goes to travel expenses and salaries for editors and a research staff of about 36 Harvard students. Unlike most of its competitors. Let's Go sends its researchers to places around the world every summer, to report the most timely information on prices and travel conditions.

The Let's Go series has expanded remarkably in the last five years, from four to 10 books. The traditional consumer favorites--Let's Go Europe and Let's Go USA--remain the biggest sellers, but more specialized regional guides to places ranging from Israel and Egypt to Spain. Portugal and Morocco have also garnered sizeable audiences. A new guide on Mexico, which Let's Go staffers have been working on for two years, will hit bookstores across the country this fall.

While the expansion has been great news business wise, editors say they probably will not add books anytime soon on India or Vietnam--as a more unconventional staff did in the late '60s.

"One problem with expansion is that the Harvard student body does not expand with us. I don't think we could get many more good researchers than we do now," says Fishbein.

More than 100 students sought Let's Go positions this year. After completing a detailed seven-page application, about 80 of them get interviews.

Foreign language proficiency might seem to be the prime criterion, but other qualities top the editors' list. The applicants must demonstrate writing ability--the application requires two essays and one editing sample--and "rugged" travel experience.

"What's most important is durability--the ability to be on your own and walking around for eight or 10 hours a day," says Susan Whitlock '84, managing editor for the USA guide, which sold about 30,000 copies last year.

Each researcher spends eight to 11 weeks in an area, following an itinerary determined during the spring. They search out cheap restaurants and accomodations and interesting sights, and take down practical information about trains and post offices.

In travelling, researchers try to find the least expensive and most hospitable places for students. In the U.S., this means staying at Motel 6's or KOA campgrounds. It may mean eating a lot of bad, cheap food to find those few good, cheap eateries.

"We aim for the most homestyle kinds of places, usually family run with just good, simple food," says Fishbein. "We even list it if its lousy, we make sure and say 'lousy, but cheap,'" he adds.

Investigators also try to convey an idea of a city's individual character and social life, and write up sections on the best nightclubs, hangouts, gay bars and discos.