Jess and Leslie's friendship is the central theme of Bridge to Terabithia. Their friendship is delightful on a simple level, their childish exploits fraught with amusement and joy. However, we cannot simply call Bridge to Terabithia a monument to the carefree pleasures of childhood, because that would miss one of the main points of the story. The reason that Jess and Leslie's friendship is so magical is because it allows them to rejoice in childhood and to escape the rest of the pressures that bear down on them so heavily in the rest of their lives. Jess, in particular, leads a life full of everyday hardship and dissatisfaction. We sense that before Leslie came along, he was in danger of sinking under the weight of these combined pressures and reluctantly accepting conformity.
This is the essential beauty of their friendship: it allows both Leslie and Jess, particularly Jess, to find their true selves. This seems to be Paterson's central point about friendship—that it allows friends to expand, to explore new dimensions of one's character as a result of the other person's pushing one in new directions. For example, Jess's artistic abilities are strengthened by Leslie's imagination, which provides perfect fodder for new and innovative artwork, and Leslie's strength and courage are tested and developed when Jess encourages her to help Janice Avery. Jess discovers in himself an aptitude for invention and creativity; Leslie uncovers a desire for spirituality when Jess brings her to church. Rather counterintuitively, Paterson suggests that individuality is difficult to find on one's own, because then one has no aid in combating societal and other external pressures and forces which would attempt to destroy one's individuality. Rather, in a friendship, one discovers new aspects of oneself and helps the other person to discover new aspects of him/herself as well. This is particularly important in an adolescent friendship such as the one described in Bridge to Terabithia, because those are the formative years, when much of one's adult character is determined. A friendship such as Jess and Leslie share allows the two to become comfortable with themselves, to discover who they really are without worries that what they find will not fit into the "proper" mold. Ultimately, each member of such a friendship is strengthened and developed by the friendship.
Childhood is a corollary to the theme of friendship in the book. As mentioned before, some people might have a tendency to breezily summarize childhood as a time of carefree bliss, when nothing could go wrong. This might be reinforced by the idealized times that Leslie and Jess spend in Terabithia, which seem to be the epitome of untroubled childhood joy. However, Paterson recognizes that this is far from being true all the time—in fact, the main attraction of Terabithia is that it allows the children to escape the "real world," which is apparently nearly as full of pain and sorrow for children as for adults. Sometimes this is played down a bit, as when May Belle is devastated when Janice Avery steals her Twinkies; however, the character of Janice herself is perfect proof that childhood is not always perfect, given her father's violent abuse of her. Jess, too, struggles with very pervasive problems of identity imposed by his family and classmates. Leslie must contend with the disdain of her classmates and the wavering attention of her parents, whose work often dominates their lives. Paterson clearly encourages us to take a look beyond the stereotype of idealized childhood and to realize that children deal with problems just as pressing as those that adults face. Our priorities shift as we grow older, so we have a tendency to downplay the crises of childhood as unimportant, even though they are very real and important to the children who suffer them.
Jess's main struggle in the book is to discover his true identity when faced with the demands of his family and society in general. The push is for him to conform—to discard his artistic talent and concentrate instead on those pursuits that are either more "manly" or which will be more practically useful to the family. His classmates expect him to come out of a certain mold as well, to watch the Washington Redskins on television and hang with the guys and act tough. However, it's Jess misfortune—or, to offer an alternate point of view, his good luck—not to fit this mold particularly well, and he feels trapped, finding running to be the only safe outlet for his own talents and inclinations. When Leslie comes along, she helps Jess to escape from the crushing pressures of conformity. Her parents' background as free-spirited near- hippies has given her a great deal of freedom and personal choice, and she opens Jess's eyes to the possibilities that exist for him as well. When she dies, he is crushed, but he has gained enough strength and sense of self through his friendship with her to carry on without her and not lose touch with all she has taught him.
Gender role is a motif that plays off the idea of conformity. Jess is expected to fit into a certain mold, but that mold is a distinctly masculine one. Jess's father is scornful of his artistic ability, calling it a girl's pastime. Jess's classmates snigger if he shows a tendency to want to avoid brawling when possible. Jess is expected to be responsible, stoic, and strong, and to be ready to shoulder the burden of responsibility for the family that his father has carried all these years. Leslie meets with the family's disapproval because she doesn't fit easily into a feminine category, with her short hair and athletic ability. However, this is part of what draws Jess to her. She has a liberating force that she exerts over all his cramped confinement. Leslie shows him that he does not need to fulfill a peculiarly masculine role, and that he is free to be himself without reference to gender stereotypes.
Education is portrayed rather dubiously throughout Bridge to Terabithia. Certainly the area in which Jess lives is not strong on education: the rural area is dirt-poor, with little money to fund a school system, and most of the residents are uneducated as well, farmers by destiny and by trade. Jess has very little exposure to intellectual thirst and curiosity until he meets the Burkes. They are all extremely intelligent and highly educated, a fact that sets Jess reeling at first. Certainly their education forms a crucial difference between them and the rest of the people in the area.