The main theme may as well be hidden in the title. Clay is a quiet and reserved person who, determined to answer the question about his father's disappearance, decides to build a bridge. This bridge is not only a physical representation of conquering one’s fears, but also a metaphorical bridge for repairing broken relationships: for forgiveness, love and family and a bridge from a traumatic past to a better future.

Essentially, Clay builds a bridge that he hopes will bring him to his father, to the people he loves and respects, and to the deepest parts of his mind. On the road, he will learn that every person is basically a bridge; we go wherever we’re destined to go. Sometimes we’re even lucky enough to go wherever we want to go. The author tells us how we must make the journey through our lives on our own, but how we must never forget to bring our deepest emotions and all of those we love with us, as well.

Thus, the significance of family is the most important theme in the novel. The mother of the Dunbar brothers, Penny, died when they were young, and their father, Michael, disappeared from their lives. The author tell us how the boys cope with loss and sorrow form an early age and how they learn to move on with their lives. It shows how growing up without a parent might affect a child’s life and how even the smallest and at the time insignificant moments can shape us in who we become. Through the Dunbar's daily escapades, vivid memories, and tragicomic scenes, we learn the story of one dysfunctional family from Australia that rediscovers the importance of love and family.