This is a 1982 limited edition art print by David Hockney entitled Red Square and the Forbidden City that was produced to accompany the book China Diary by Stephen Spender that was published by Thames and Hudson Ltd in London. 1000 copies were printed and the slipcased book was signed by both Spender and Hockney. The estimate is based on actual recent past recorded auction sales of comparables. Retail 'asking prices' can be higher and vary.