In 1958, the architects Alison and Peter Smithson bought a derelict cottage on the Fonthill Estate in Wiltshire, south-west England. Over four years they transformed it into a country home for their young family, and called it Upper Lawn or the Solar Pavilion. The project is revisited in a new book. Upper Lawn, Solar Pavilion by Alison and Peter Smithson is published via MACK Books. All photographs: Alison and Peter Smithson/MACK Books