The boys knew, everybody knew: blacks frequented the beach at Twenty-Sixth Street; whites swam at the beach on Twenty-Ninth Street.
-- Claire Hartfield (The Beach)

Importance: Here, Hartfield illustrates the invisible line segregating blacks and whites in Chicago in the early twentieth century: her use of the word 'knew' shows that these divisions were internalized and taken for granted by those who lived during this time period. As such, everyone 'knew' not to cross over into the other race's territory, when it could be avoided.

It seemed that something had come over black people after fighting the Great War in Europe during the previous few years; when the war was over, they seemed to think they could go anywhere.
-- Claire Hartfield (The Beach)

Importance: Hartfield is revealing to the reader some of the shifting attitudes of both black and white people in 1919, filling in historical gaps when necessary. She is here hinting at the issue of black patriotism during World War...