It is not a review, I got it from amazon:
Set in the mysterious shadowed city of New Orleans in the years immediately following the Louisiana Purchase, George Washington Cable's classic novel of the Old South traces the declining fortunes of a family and their society as they struggle with long-standing divisions of race and class and with the ideals of democracy and liberty imposed by their new American rulers.

The hero of the novel, Joseph Frowenfeld, is a young scientist who moves to Louisiana to make his fortune. An outsider, Frowenfeld learns the ways of the Creoles and of the few Americans in the city through his acquaintance with the proud Grandissime family. He comes to know Honore Grandissime, the young leader of the clan, as well as his half-brother, a prosperous free man of color also named Honore, who has the power to rescue his relations from financial ruin.