Roy was a serious student of the history and conservation of windmills since 1974 when he took responsibility for the windmill in Skidby in East Yorkshire. His wide research led to his books "East Yorkshire Windmills" (1985) and "Windmills in Yorkshire" (2009) with Laurence Turner.
He published "The Industrial Windmill in Britain" in 2005 and researched the uses of wind power across Britain and many parts of East and West Europe. He presented papers to TIMS and was for three years chairman of the SPAB Mills Section. A retired solicitor, he had an abiding interest in the work of the Hull millwrights Messrs Norman and Smithson.
Roy Gregory died 8 November 2013.