A Lost Lady is primarily a transcendent of realism, arriving shortly before The Great Gatsby which shares many of its characteristics. A characteristic of this type of novel is that the society is in transition from an old culture to a new, a power struggle that causes there to be a preference for an idealized past. It leads to a conflict between idealism and coarseness. Although Cather is better known for other works about Nebraska, this is her first modernist novel.
Cather's work falls into the category of "literary regionalism", a narrow account of a culture within a national experience. At the time she was writing, 1923, there are really only two veins of cultural description, the international or pan-national account, and the regional national. The description of national culture came later.
This form of regionalist writing can be traced back to Sir Walter Scott. It is a reaction to the French Revolution and Napoleon's conquests, both of which tried to universalize European culture. In order to create a distinct culture for a region, writers inevitably were forced to study a defeated culture. This gives rise to the myth of the lost culture, in this novel the American west during the pioneering days. The myth is structured around a vanished world, a short-lived world, and the culture is defined by that world's defeats.
Cather's A Lost Lady is written towards the end of the Age of Reform, as Hofstadter termed it. This is an age when the small-town gentry, the bankers and lawyers, are being swept aside by the inevitable growth of a national rather than a regional elite. They feel their status collapse during the 20th century as the national ceiling on wealth rises significantly.
Within this world is the conflict between the old culture and the new, espoused by Captain Forrester and Ivy Peters, respectively. This can be seen by the difference in the type of commerce done by each man: Ivy travels all over the United States, a part of the national economy, whereas the Captain is in charge of only one regional bank. The new world is one of arrogance, scale and social Darwinism. There is a lack of philosophy within the new culture, and as often happens the new culture will adapt the ideas of the gentile tradition and modify them. These thinned out ideas become pieties, such as "gentleman", which has no meaning in the new world but is necessary to understand it.