4Winds Tours Ooffers cycling, barging, spring flower, and brewery tours in Holland and France as well as hiking/biking tours in Austria, Ireland, and Denmark. http://www.4windstours.com/

Academic Tours Offering cultural and archaelogical tours in Europe. http://www.academictours.com/

Action Factory Offers trips throughout Asia and Europe. http://www.actionfactory.com/

Adelanta Travel Services Customised group tours of Great Britain (UK) and Western Europe. http://www.adelanta.co.uk/

ADVENT Tours Offers a range of subject-based educational tours covering topics such as English, arts, geography, history, languages, and drama. http://www.advent-tours.com/

Adventures on Skis Offers skiing, biking, hiking, equestrian, and other outdoor vacations in the Alps, Europe, South America, and the Rockies. http://www.adventuresonskis.com/

Agency Plus Features Budapest excursions and tours across Hungary. http://www.agency.hu/

Alpin Travel Offers heli-ski and heli-snowboard packages at the Gudauri Caucasus, Republic of Georgia. http://www.alpintravel.ch/

Alpine Adventure Tours Offers cycling tours in France and Italy and cross-country ski tours in Europe. http://www.alpineadventuretours.com/

Alpine Interface Offers trekking and hiking in the Alps, walking tours in Provence, adventure trekking in Nepal, and sea kayaking in Mexico. http://www.alpineinterface.com/

Alternative Holidays Lesbian and gay travel company offering an array of vacation packages. http://www.alternative-holidays.com/

Altius Offers outdoor adventures including horse riding, rock climbing, hiking in the Alps, skiing, and paragliding. http://www.altius.pl/

American Tours & Travel, Inc. Specializes in student group travel throughout the U.S., Mexico, and Europe. http://www.travelgroups.com/

Anglia Battlefield Tours Offers battlefield and pilgrimage tours in Britain and Europe for schools, colleges, and the general public. http://www.angliabattlefields.co.uk/

Any Mountain Tours Offers ski vacation and theme packages throughout the western U.S. and Canada. http://www.anymtn.com/

Arc Boutant Offers a summer program in architectural restoration and historic preservation in Europe. Students live and work on-site. http://www.arcboutant.org/

Archetours, Inc. Architectural tours to destinations in Europe and Japan. http://www.archetours.com/

Art of Travel Offers a variety of international and domestic tours, including guided visits through artistic and architectural landmarks. http://www.art-of-travel.com/

ATG Oxford Offers a range of walking and cycling tours and special interest holidays in Europe and further afield. http://www.atg-oxford.co.uk/

Atlantik Tours Offers circle tours, shore excursions, incentive travel in Iceland and daytours to Greenland. http://www.atlantik.is/