A bookmobile or mobile library is a large vehicle designed for use as a library. They are designed to hold books on shelves so that when the vehicle is parked the books can be accessed by readers. They usually have sufficient space that people can also sit and read books inside them. Mobile libraries are often used to provide library services to villages and city suburbs without library buildings. They also service those who have difficulty accessing libraries, with retirement homes being common stops. They may also carry other information or computer equipment, such as might be found in a library. Some libraries also use their bookmobiles to deliver materials, such as audio books and large print novels, to homebound patrons who don't have anyone to go to the library for them.

The first Bookmobile in the United States was developed by Mary Lemist Titcomb (1857-1932). While employed at the Washington County, Maryland Free Library, Titcomb was concerned that the library was not reaching all of the people it could. So, she worked on a plan for a book wagon. In 1905 the Washington County Free Library provided the first book wagon in the nation to residents by taking the books directly to their homes in remote parts of the county. (Maryland State Archives, Maryland Women's Hall of Fame, Washington County Free Library)

The Gerstenslager company specialized in building mobile libraries and similar vehicles in the 1950s.