People vs. nature is a theme that refers to the relationship that people, as exemplified by the main characters of the book, have with their natural surroundings. Often the people vs. nature theme examines either society's need to control nature or the destruction of nature by people. Also, it can explore the need for nature in people's lives.
An exploration of the individual vs. society is a theme often characterized by a character's views, habits or needs being contrary to those of others, causing the person to be at war with society. This theme is expressed in a number of ways, including society's defining a person by his position within society, or a character's destiny being affected by the influences of society.
Good vs. evil is a common theme that explores the nature of good and evil and of people's relationships with the divine. Classical literature often pits a character directly against the gods, usually with tragic consequences. The idea of predestination explores the hand of the divine at work in a world that pits good vs. evil.
Internal conflict that a character works to overcome exemplifies this thematic category. Coming-of-age stories tend to fit into this conflict genre. Another type of story in this category is a character trait's causing conflict and the character's struggle to change that undesirable trait. Other internal conflict themes include being true to yourself and reaching your full potential.