The Ordnance Survey started life in Britain in the late eighteenth century, and its original purpose was military in nature. It traces its origins to 1746 when King George II commissioned a military survey of the Scottish highlands. Almost fifty years later, the Board of Ordnance (the defense ministry at the time) began a survey of England's southern coasts, which were vulnerable to attack from nations on the Continent. The real gems here are the two full-length books that visitors can read at their leisure. They are "A History of the Ordnance Survey" by W.A. Seymour and "Ordnance Survey: Map Makers to Britain since 1791". Both works deal with the political and military implications of the Survey, along with providing information on the more technical aspects of surveying work.