"What is character but the determination of incident? What is incident but the illustration of character?" James asks in his essay "The Art of Fiction." And, in a notebook entry describing the "germ" of The Ambassadors, James sees "the idea of the tale being the revolution that takes place in the poor man [Strether], the impression made on him by the particular experience, the incident in which this revolution and this impression embody themselves. . . . They are determined by certain circumstances, and they produce a situation, his issue from which is the little drama." The Ambassadors, consequently, is less concerned with facts or events than with situations and impressions. Its action derives essentially from character; the "plot" of the novel is therefore relatively simple compared to its subtleties of characterization.
The central character is of course Lambert Strether, and the book is wholly concerned with the experience of his embassy to Europe; the narrative never reaches beyond the sphere of his thought. Because Strether's point of view is the angle of vision through which the story is told, the change in his attitude results from the change in his vision; and Strether's vision is shared by the reader. Maria Gostrey, Chad, Madame de Vionnet, and all of the other characters are presented to the reader through the filter of Strether's consciousness. It is character alone — what Lambert Strether thinks, feels, is — that is the substance of The Ambassadors.