7 East 96th Street
Thus all good architecture and good decoration (which, it must never be forgotten, is only interior architecture) must be based on rhythm and logic. A house, or room, must be planned as it is because it could not, in reason, be otherwise; must be decorated as it is because no other decoration would harmonize as well with the plan.
Before beginning to decorate a room it is essential to consider for what purpose the room is to be used. It is not enough to ticket it with some such general designation as "library," "drawing-room," or "den." The individual tastes and habits of the people who are to occupy it must be taken into account; it must be not "a library," or "a drawing-room," but the library or the drawing-room best suited to the master or mistress of the house which is being decorated. Individuality in house-furnishing has seldom been more harped upon than at the present time.
The Decoration of Houses, by Edith Wharton and Ogden Codman
1914
(all text taken from the book courtesy of Gutenberg.org)
Rooms may be decorated in two ways: by a superficial application of ornament totally independent of structure, or by means of those architectural features which are part of the organism of every house, inside as well as out.