When we think of a library, we picture a building on a street or perhaps a room in a school. But some libraries aren't kept behind four walls. Some move from place to place in the most remarkable ways: by bus, by boat, by elephant, by donkey, by train, even by wheelbarrow. These unusual mobile libraries are often the only way that books can be brought to people in remote areas, such as the mountains of Thailand, the Gobi Desert of Mongolia, or rural areas of Zimbabwe. In places such as these, the arrival of the libraries is a major and much anticipated event. But the books would never reach the people without the hard work of dedicated librarians and volunteers.Margriet Ruurs, writer and educator, contacted librarians around the world and asked them to share stories about their libraries.