The World According to Garp is a sprawling, episodic novel, with the colorful, sometimes roguish, but endearing illegitimate son of Jenny Fields as its hero. It is also a Bildungsroman, a novel about the formation of a writer, Irving’s portrait of the artist. Its episodes point toward attempts to triumph over the “Under Toad” of death and obscurity. Garp at first seeks to accomplish this through his fiction but comes to the conclusion that writing an immortal novel is not the only way to find meaning in life. In this, Garp adapts Aurelian stoicism to his own needs, recognizing the necessity of rising above one’s own pain to live in closer harmony with nature. Jenny knows this instinctively; her son learns it through bitter experience.

The Pension Grillparzer obliquely introduces the “Under Toad” theme through Duna, the trained bear which eventually becomes clawless, toothless, and unwanted. Vienna, the place of Aurelius’s death, is a city without hope or the possibility of regaining its former eminence. It is a city of the old, the corrupt, and it mirrors Garp’s own early life.

Gender Roles
Irving's novel examines the significance of gender roles in American society. Jenny's independence as a woman is frowned-upon by both her family and society in general. Young women usually didn't live alone in the 1940s. For example, it is immediately assumed that Jenny has some relationship to the soldier she stabs in the movie theater. Jenny resents the idea that a woman has to be "either somebody's wife or somebody's whore." In fact, Jenny exhibits some traditionally masculine traits: she is strong, plainspoken, and willful. This is demonstrated when her lack of a husband doesn't prevent her from getting pregnant. Her refusal to allow society to pigeonhole her because of her gender stirs great controversy and ultimately leads to her assassination. Alternately, Jenny's son Garp reverses gender roles. Garp, although he is very masculine, assumes the traditionally female role of domestic caretaker. Helen works while Garp cleans, cooks, and cares for the children. Although the arrangement is simply a matter of convenience (Garp can also write as he performs the domestic chores), the role of "househusband" was unusual at the time. Finally, the character of Roberta Muldoon demonstrates the most drastic gender reversal in the novel. The former football player is obviously happy to be a female.

Death and Disfigurement
Irving's novel ends with the words, "in the world according to Garp, we are all terminal cases." Irving seems almost obsessed with the absurdity and randomness of violence and death. The author often details the deaths of his characters in The World According to Garp almost immediately after introducing them. Garp himself is conceived amongst dying and disfigured men in the intensive care unit of Boston Mercy. He is disfigured as a child when Bonkers the dog bites off part of his ear. Garp is disgusted by the self-mutilation of the Ellen Jamesians; he is more sympathetic to the gender-changing mutilation performed on Roberta Muldoon by doctors. His family is traumatized by the car accident that kills Walt. Duncan loses one of his eyes in the accident, and Michael Milton is horribly injured. Late in the novel, the concept of the Under Toad is introduced. The Under Toad, a play on the word "undertow," is the code word the Garps use for a powerful feeling of dread. Garp "smells" the Under Toad when he receives the phone call in Austria informing him of Jenny's assassination. Garp himself is assassinated near the end of the novel. Finally, the epilogue details the various deaths of most of the remaining characters. Irving leaves very few loose ends.

Love and Lust
The World According to Garp is concerned with all the various types of love. The love between parents and children is demonstrated first by the relationship between Jenny and Garp and then by the relationship Helen and Garp have with their children. Garp loves his children so powerfully that he is over-protective. Irving also examines the love between husband and wife. Garp and Helen love each other so fiercely that their marriage is able to withstand several catastrophes. There are also many loving friendships in the book; for instance, Garp and Roberta Muldoon become extremely close and loving friends. The novel also examines the nature of lust. Garp believes that his mother is somewhat cold because she doesn't experience lust, but Jenny recognizes that lust can often be disastrous. She takes care of dozens of women at Dog's Head Harbor who have been victims of lust. Garp's own life is affected by lust. First of all, Garp contracts gonorrhea in Austria when he runs into a trio of American tourists and he can't control his baser instincts. Garp also threatens his marriage when he has brief flings with babysitters. Finally, Helen's lust leads her into an affair that almost destroys the family.

Art and Creativity
Garp's life as a writer is an important subject in the novel. He often struggles with his art. He has difficulty writing in Vienna as his mother churns out her autobiography. However, he is finally inspired enough to write a charming short story, "The Pension Grillparzer." Irving uses the device of fiction within fiction to display Garp's work in the novel. The complete texts of "The Pension Grillparzer" and the essay "Vigilance" are part of the novel. In addition, the entire first chapter of Garp's novel, The World According to Bensenhaver, is chapter 15 of The World According to Garp. The plots of novels both written and unwritten are discussed as well. Garp, like many authors, is cursed by writer's block at various moments in his career. He also uses his art as a catharsis for personal tragedy when he writes The World According to Bensenhaver. He appears to be entering a productive stage in his career, with plans for three novels, shortly before he is murdered.

Despite the violence of some of the scenes of The World According to Garp, the tone of the novel is frequently comic, and the values underlying the world Garp attempts to create in his life and his novels are the essential ones of justice, kind fairness, and love. Hence, one of the themes is the difficulty of maintaining those values in a world that seems to foster extremism and random violence. One answer, here as in Irving's other novels, is the nurturing and perpetuation of the family. Jenny Fields is a good mother; Garp is a good father; the proper care of children may be a defense against chaos. Despite the fact that Garp and his wife Helen are unfaithful to each other during the course of the novel, Irving makes it clear that their commitment to each other is deep and abiding. Another, more lighthearted theme is the confusion of illusion and reality, which Irving conveys in part by having his main character write a novel within the novel. The World According to Bensenbaver is T. S. Garp's novel, and this world within a world reminds the reader that each person's perception of reality may differ from that of others, making order difficult to maintain, as, in the end, Garp is unable to keep his children or himself from harm.