The reasons for buying a second home are universal. Many people seek a place to relax and escape everyday routine. A second home may also represent a step back to nature.
"Most of the Germans I met in Sweden were carrying a rather idyllic image of Sweden and were disappointed, because the Swedish countryside is more modern than they expected," said Dieter Müller, who co-edited the tourism book with Hall.
"However, I think they created their own little Sweden somewhere in the Småland forests," added Müller, who is German and teaches geography at Umeå University in Sweden.
Many people also buy a second home to retire there. Some southern European countries, like Portugal and Spain, have seen a dramatic influx of retirees from northern European countries, primarily England and Germany. The newcomers are lured by the warm weather, pristine beaches, and abundant golf courses.
"One of the most interesting aspects about tourism in Portugal is how many people who holiday there then go on to buy a second home or even retire there," Hall, the Tourism, Mobility and Second Homes co-editor, said.
So large is the English expatriate population in Algarve, in southern Portugal, that many British political parties routinely come to seek donations for political campaigns back in the U.K.
There is little doubt that second-home tourism can be a major contributor to local economies, boosting local service supply and keeping local entrepreneurs in business.
It can also ensure the survival of rural areas by filling vacancies caused by rural out-migration. In Finland the countryside population declined by 31 percent to about 900,000 between 1980 and 2000. At the same time the number of people using second homes had increased by 79 percent to more than 1.8 million.
However, second homes can also increase the tax burden for the local population. In some areas housing prices may rise beyond the means of locals.
Sometimes social resentment may also develop toward second-home owners, who may be seen as outsiders or even invaders. Many people who buy second homes in foreign countries do not learn the local language. This is particularly true in places like Portugal and Spain, where some resort communities have been completely taken over by English and German settlers.
In Ireland's Gaeltachtthe country's seven, historically Irish-speaking regions along its western seaboardthe local tongue, Gaeltacht Irish, is slowly ceding ground to English as the language of daily life, mainly because of the number of non-Irish speakers moving into Gaeltacht communities.
The environmental effects of second-home tourism may be mixed.
Second-home owners often use indigenous architecture in restoring buildings that may otherwise fall into disrepair. Many second-home owners are committed to environmental issues, and second-home tourism has, in many places, led to the protection of natural areas and wildlife, some researchers say.
"The capacity of [popular second-home tourism destinations such as] southern Portugal to host so many people may be greater than some of the more environmentally sensitive areas in the tourists' own countries," Hall said.
But the demand for development of second homes in previously untouched areas, from the plains of Montana to the north woods of Maine, is also seen as a crisis by many environmental and conservation groups.
Second-home ownership in the United States is less common than it is in Europe.
"Relatively speaking, this form of tourism is much smaller than other forms, because only a small portion of the U.S. public owns a second home in the traditional form," said Dallen Timothy, a professor at the School of Community Resources and Development at Arizona State University in Tempe.
Still, second-home ownership in the United States has almost doubled in the past 35 years. In 2001 there were more than 3.5 million second homes in the country.
Most U.S. second homes developed as a result of people escaping either intense summer heat or bitterly cold winters. Native Americans commonly sought refuge away from their normal abodes. For example, Cape May, New Jersey, was a popular seaside refuge for the Leni Lenape Indians centuries before the beach homes of the 1800s were built there.
A particularly popular form of second-home ownership in the U.S. is time-shares, where consumers purchase periods of time at a property. Since the late 1970s time-shares have grown between 14 and 17 percent per year. Today the industry is worth more than four billion dollars in the U.S.
There has also been a strong growth in U.S.-owned homes abroad. Americans have long owned vacation homes in Mexico, particularly around Acapulco and Puerto Vallarta. But today some Americans are settling in more exotic territory, such as the rain forests of Cayo in English-speaking areas of Belize.
Researchers say that a demographic shift will have a substantial impact on second-home tourism. As of 2000 11 percent of the world's population was 60 years old and above. By 2050 that figure is estimated to rise to 20 percent.
Particular types of tourism geared toward retirees, such as recreational vehicle cruising, should continue to grow in popularity. But second homes that go on to become permanent retirement homes may also become increasingly important in tourism-development strategies, researchers say.