Pierre et Jean is a realist work, notably so by the subjects on which it treats, including knowledge of one's heredity (whether one is a legitimate son or a bastard), the bourgeoisie, and the problems stemming from money.
Pierre and Jean are the sons of Gérôme Roland, a jeweller who has retired to Le Havre, and his wife Louise, of a middle-class French family.
This investigation sparks violent reactions in Pierre, whose external appearance vis-a-vis his mother visibly changes.
(Works such as Don Quixote, The Three Musketeers, and Madame Bovary are listed to illustrate the diversity of the form.)
A writer, he believes, should carefully pick the appropriate moments of their characters' lives in order to create a story, discarding the numerous day-to-day occurrences which serve no use to this purpose.