Barter Books is a second-hand bookshop in the historic English market town of Alnwick, Northumberland, owned and run by Stuart and Mary Manley. It has over 350,000 visitors a year, 40% of whom are from outside the area, and is one of the largest second-hand bookshops in Europe. It is considered a local tourist attraction and has been described as "the British Library of second-hand bookshops."