The word Bildungsroman is German in origin, made up of the words bildung, which means formation or education, and roman, which means novel. Thus, a Bildungsroman is a story that details the formation of the protagonist's character and identity. The main character is often introduced as a child (or, at least, someone who is relatively immature compared to a typical adult). This character has experiences which influence and affect them, likely resulting in some kind of personal crisis. Finally, they overcome or respond to the crisis in such a way that their identity and maturity develop, and they take their place within the world.

Alienation from one's society or family is a common theme in these stories, as this can easily produce crises of confidence to which the protagonist must respond. Class structure and poverty are also common themes for the same reason. Unrequited love or sexual frustration can also produce these effects.

Bildung ("education") + Roman (novel) = a novel dealing with a young person's formative years in terms:

• education (spiritual, ethical)
• maturation (physical, emotional)
• coming-of-age (apprenticeship, initiation, induction)
• sexually (virgin to maturity or rejection)
• rebellion (vs. society, family, institutions, self, God)
• self-discovery (a trial by fire)
• identity (existential)

Examples:

Catcher in the Rye

The Bell Jar

Invisible Man

Bless Me, Ultima

Portrait of an Artist as a Young Man

The enotes Study Guide on bildungsroman writing suggests the following themes occur regularly in novels of this type:

• Coming of Age and Apprenticeship
• Education
• Identity and the Self
• Journey
• Love
• Search for the Meaning of Life

A novel of this type basically follows a character from childhood or adolescence to adulthood.  According to The Concise Oxford Dictionary of Literary Terms, the bildungsroman (which means "formation-novel" in German), was best established by Goethe with his Wilhelm Meisters Lehrjahre (1795-6).  Thomas Mann is considered one of the best successors to Geothe in this area.

The bildungsroman novel is closely related to the traditional picaresque novel, except that it is more philosophical in nature.