Ceaseless ferreting among archives, drawings, objects and buildings for at least fifty years has made John Harris a dazzling discoverer of facts about British architects, interior designers and garden designers. Moving Rooms, about architectural salvages in Britain and America, is the latest of over fifteen books, and a triumph.

‘Period rooms’ in America are at the centre of this fascinating book, the first on this topic, yet Harris has a love–hate relationship with them. He notes, for example, that they are peep boxes or stage sets with only three sides, generally without original ceilings or correct lighting, and he suggests that if their eighteenth-century inhabitants could be invited back to them, they would barely recognise them. Until at least the 1950s such rooms were shown without any history of provenance or use, while museum directors or curators, entirely at the mercy of dealers in New York, London or Paris, rarely examined the rooms for authenticity as they would with paintings or sculpture. (Harris admits that even he was deceived by the saloon supposedly from Kempshott Park, Hampshire, at the City Art Museum, St Louis, Missouri.)

Why were all these rooms available? Harris gives some unhappy reasons, from the effects of the Agricultural Depression which began to be felt in 1873, to the deaths of several hundred thousand officers in the First World War, ‘dealing the country estate a mortal blow’. It was no coincidence that