Alis Hawkins will talk about crime fiction of the 1920s and 1930s and perhaps slide either side of those dates as well; Agatha Christie leaps to mind, of course, but other rooms in the house have Margery Allingham, Dorothy L Sayers, Ngaio Matsh, Georgette Heyer, John Dickson Carr and Ronald Knox. But despite the Golden Age being back in the day, most of these writers were still working immediately postwar and later.  Knox it was who codified some rules of the game [jokingly, largely, I would think]: no Chinaman, twins, spiritual intervention and no more than one secret room or passageway in a house.