sentences:  In 1950 books about the waterways started to appear, to inform the public about their plight, with Rolt producing "The Inland Waterways of England", Aickman producing "Know your Waterways", and Hadfield producing "Introducing Canals".Later the same year, his book "British Canals" appeared, which ultimately was expanded into a comprehensive series of books about canals throughout Great Britain.Hadfield parted company with the IWA in 1951, after he, Rolt and others signed a memorandum suggesting that the organisation needed to have a policy of "priorities".