Kelham Island is at the heart of Sheffield's early development. It was created in the 12th century by the Lord of the manor, Sir William de Lovetot, when a mill-race, or goit, was excavated by the river don, and a weir was constructed to raise the water level. Its role was to provide waterpower for the town corn mill. It's name derives from Kelham Homer, the town armourer, who had two cutlery wheels on the Island in the 17th century. The book traces the history from its beginnings to the present day and places it in its historical and economic contexts at different stages of its evolution. It analyses the reasons for its construction and when in the 12th century it was constructed. It also evaluates its relative efficiency in comparison to other water mills locally and further afield. The book also examines later uses of the goit and its buildings including a silk mill, a workhouse, a power station and the kelham Island Museum.