CHICAGO.- Whether commissioned by others or individually inspired, photographers have consistently been interested in documenting political and social subjects that bolster, record, or even critique a nation’s identity. Commissioned by Napoleon III, Gustave Le Gray photographed French military exercises in order to boost pride in the government's defenses, whereas August Sander, under his own impetus, set out to catalog a cross section of German society. Robert Frank took a critical perspective in The Americans, which presented life in the United States as conformist, shallow, and divided. These and other projects, aiming to picture and thereby understand a nation, have inspired this exhibition, which is drawn entirely from the museum's collection.