Hilary Bradt and her former husband George Bradt became book publishers by accident, writing their first travel guide on a river barge floating down a tributary of the Amazon while vacationing in Peru in 1974. Having discovered an out-of-the-way hiking trail, they set out to document it for fellow travel aficionados and produced Backpacking Along Ancient Ways in Peru and Bolivia. More a pamphlet than a book, the Bradts published it without a spine.

London-based Bradt Guides has come a long way since then, with over 140 titles in print, covering more than 200 countries. The press has a reputation for publishing guides about unusual destinations and for promoting the cause of sustainable travel. “We champion the idea that, in addition to promoting tourism, guidebook authors can have a positive impact on the host country by listing charities that welcome volunteers or donations of local currency or medicines,” explained Hilary Bradt, who has run the company on her own since her marriage ended in 1980. “We devised the phrase ‘traveling positively’ to describe these efforts.”

When the company began, sales trips in the U.S. were done by Greyhound bus. “We’d buy a cheap coast-to-coast ticket, sleep on the bus at night, and get off at the major American cities to visit bookstores during the day,” Bradt said. “Sometimes we camped in city parks or slept at a YMCA.” The personal sacrifices paid off. ”No one else was publishing our sort of travel guides at that time, so the reception was good and we sold a lot of books,” she said. The result? When the fourth Bradt guide was published, it had a spine.

Bradt released early guides to previously off-the-beaten-path destinations that are now popular, including Vietnam, Mozambique, Tanzania, and Botswana. Today, more than half of the Bradt Guides, distributed in the U.S. by Globe Pequot Press, have little or no competition. It has 33 titles on African countries and a guidebook on North Korea. “Our books are different from those of other publishers because of our detailed background information; our travelers’ tales, which give the feeling of what it’s like to be in each country; and the authors’ voice,” said Bradt. “We’re very fussy about who we commission to write a Bradt guide. Our authors include former British ambassadors and tour operators.” The company, which has a staff of 16, publishes about 40 new titles annually, one-third of which are new; the rest are updated editions.

Like other travel book publishers, Bradt is meeting the demands of the evolving digital formats. “We now publish our books in both print and e formats,” said managing director Donald Greig. “But it’s just the beginning of the story. Tablets offer so many great opportunities to deliver different types of content that we are exploring ways in which to exploit the technology to best effect. The majority of our sales are still of print books, but we expect digital to continue growing.” Bradt’s bestsellers in 2013 include guides to Haiti, Iceland, Ethiopia, Ghana, Rwanda, Uganda, and Tanzania. After 40 years of publishing, Hilary Bradt attributed her success to “being different.” She noted, “Travelers and vacationers are getting increasingly adventurous, and our fans know we’re always coming up with something new.”

Travelers Bookcase in Los Angeles is a fan of the Bradt guides. “Not five minutes ago I sold a copy of their guide to Flanders,” said co-owner Greg Freitas, when contacted by PW. “Bradt fills many holes in the travel book market.”