Trauma
From the Greek word for "wound," trauma—emotional shock that follows a stressful event—is one of the most important themes in Ghost. Reynolds introduces the theme early in the novel when Castle comments on the time his father shot at him and his mother as they fled the home. The stress of this event has stayed with Castle, resurfacing several times throughout the book. Most notably, Castle's post-traumatic stress is triggered when he gets accidentally locked in the same storage room at Mr. Charles's store that he and his mother took refuge in the night the attempted shooting occurred. Castle's trauma also arises during his first track meet: Used to his coach blowing a whistle, Castle is unprepared for the starter's pistol firing loud blanks to signal the start of races. The sound returns him to the night his father shot his gun, prompting Castle to run for his life.
Shame
Shame is another major theme in Ghost. Defined as a painful feeling of distress and humiliation resulting from distress at one's own behavior or a lack of respect from others, shame first arises in the novel when Castle comments on how kids at school—particularly the bully Brandon—pick on him at school for wearing ill-fitting hand-me-down clothing and no-name brand shoes, living in Glass Manor, and coming to school with uneven haircuts provided by his unskilled mother. Being teased for these manifestations of Castle's poverty lead Castle to feel anger and embarrassment over the lack of respect others show him. Castle also acts out by stealing a pair of shoes, bringing shame upon himself in a subconscious act of self-sabotage. Ultimately, the book shows how Castle gradually sheds his shame by gaining greater confidence in his abilities and through learning to trust that his teammates will not use would-be shameful personal information against him.
Humility
Humility—a modest view of one's own importance—is another key theme in the novel. Although Castle often feels a sense of shame for who he is, the pendulum swings just as often in the opposite direction, leading Castle to be cocky and full of himself. Mr. Charles helps inflate the boy's ego, insisting that Castle will one day be a world-record holder. Castle's inflated sense of self is on display when he spontaneously joins the first Defenders practice to challenge Lu to a race, irritated to hear Coach Brody talk up Lu's talent. As a naturally gifted sprinter, Castle's bravado is to some degree warranted; however, Coach Brody makes sure to knock Castle down a peg, subjecting Castle to rigorous training that shows Castle the limits of his undeveloped athleticism. Because of the coach's influence, Castle simultaneously develops humility alongside a growing confidence. With this mix, Reynolds shows how it humility is key to inspiring an athlete to want to improve.
Discipline
Discipline is another dominant theme in Ghost. Defined both as the practice of training people to obey a code of behavior and the controlled behavior that results from that discipline, discipline enters the novel when Castle comments on his tendency to misbehave at school, which threatens his ability to stay on the track team. In order to remain a member of the Defenders, Castle must learn to be more disciplined while at school. However, he immediately gets into a physical fight with Brandon, who provokes him until he erupts in anger. Assessing that Castle has difficulty following rules, Coach Brody introduces Castle to a rigorous, structured training regimen. The coach's plan also includes punishments when Castle misbehaves, such as making him clean Coach Brody's cab and train in his old sneakers when he learns Castle stole shoes from Everything Sports. With this new system of rules, Castle receives both mental and physical training that helps him stay out of trouble at school and stay on top of his homework during rides home in the coach's cab.
Trust
Defined as faith and confidence in the reliability of someone, trust is another important theme in Ghost. Reynolds introduces the theme when Castle discusses his relationship with Mr. Charles, a local shopkeeper. During the crisis that sent Castle's father to prison, Castle and his mother took refuge in Mr. Charles's store, knowing they could trust the man to keep them safe. However, Castle and his mother distrust Coach Brody when they meet him, skeptical of the stranger's interest in developing Castle's talent as a runner. It is only through Coach Brody repeatedly proving his reliability as a mentor that Castle and his mother learn to trust that he has Castle's best interests in mind. The theme of trust also arises during the dinner the coach gives for his newbie runners: before they can eat, each athlete must share something personal with the group. By taking part in this trust exercise, the newbies bond quickly, giving up their competitive attitudes with each other in favor of the understanding and cooperation necessary to build a truly competitive team.
Overcoming Adversity
Another major theme in the novel is overcoming difficulties and misfortunes and learning to succeed. Reynolds establishes Castle's adversity early in the book, showing how Castle comes from an impoverished family that has been severely traumatized by Castle's father's alcoholism and domestic violence. Rather than treat Castle with sympathy, students at his school use his poverty as a weapon against him, leading Castle to feel as though he doesn't belong. Castle's lack of privilege also comes up when he joins the Defenders without appropriate running gear, as he doesn't want to ask his mother to sacrifice her hard-earned wages for his new hobby. Although Castle feels isolated in the adversity he faces, it turns out that Coach Brody grew up on the same block and also had an addict father who betrayed him. But despite these setbacks, Coach Brody managed to become a gold-medalist Olympian, and he believes Castle has the same capacity to overcome his misfortune.
Camaraderie
Defined as mutual friendship and trust among people who spend a significant amount of time together, camaraderie is a major theme in Ghost. Because Castle joins the Defenders as an outsider who knows nothing about track, prefers basketball, lacks real running gear, and gets on the team through an unorthodox and impromptu tryout, other teammates are initially hostile, questioning his place on the team. However, Coach Brody's trust exercise during the newbie dinner helps bridge the differences among the athletes, and a new sense of camaraderie forms. Significantly, Castle and Lu start out as nemeses, racing to see who is the fastest sprinter, but by the end of the novel, Lu is shouting encouragement to Castle as they square up to run alongside each other for Castle's first track meet. Despite the fact that most track events are performed by individual athletes, Reynolds shows how a sense of friendship and trust among a track team is crucial to helping each runner feel supported and motivated as they achieve their personal best.
