The Ambassadors consists of twelve books written originally for serial publication in monthly installments. James conceived of each of the twelve books as "a rounded medallion, in a series of a dozen, hung, with its effect of high relief, on a wall." Each book, then, can be viewed as both a complete artistic entity in itself and an integral part of the whole novel.
The first six books are concerned with Strether's gradual conversion from the values of Woollett as represented by Mrs. Newsome to the values of Paris as embodied by Madame de Vionnet. The concluding six books develop an ironic reversal in the narrative movement whereby Strether, whose original embassy was to rescue Chad from Paris and secure his return to Woollett, now finds himself unsuccessfully urging Chad to stay. Because of this balanced movement and inversion, the structure of the novel has been viewed as the shape of an hour-glass, with Paris its pinched center. While the underlying structure of the book may be said to derive from this somewhat mechanical scaffolding, further unity is provided by a more organic consideration: the point-of-view of the story, which is to say the development of Strether as the "central consciousness." It is Strether's particular consciousness, what he sees, that is the content of the story and that shapes the events of the novel. Every detail must be observed and then analyzed by Strether; the result is an intensified unity of vision, and this device both frames and interprets experience in the narrative.
James employs other structural devices to achieve symmetry in the novel; characters, for example, are contrasted for balance: Madame de Vionnet and Mrs. Newsome, Maria Gostrey and Waymarsh, Jeanne de Vionnet and Mamie Pocock, and ultimately even Strether and Chad. The most obvious contrast is of course that of Woollert and Paris.