Maturity and growing up
Paul's maturing from a teenage boy to a grown man is a central theme in the novel. His maturity comes in many different forms. He matures physically, growing taller than most of his classmates between his first and second year. Paul also experiences sexual maturity. He develops in sensuality, has his first sexual experiences, and learns to distinguish between his childhood lust for Megan and his deep, emotional love for Rosie. He also develops in his understanding of Keller's life and, consequentially, his understanding of the world. He goes from making immature jokes about Keller being a war criminal in hiding, to having a deep respect for his professor and what he has endured. Through knowing Keller, Paul comes to learn more about the cruelties of the world. He also matures in his perspective on his relationship with Keller, realizing more and more the impact Keller has had on his life.
The two pianos
Keller's room contains two pianos: a Bosendorfer grand and a peeling Wertheim upright. Keller always sits at the grand and has Paul sit at the old upright. The different pianos symbolize the gap between their musical skills. Paul continues to sit at the upright throughout his lessons, symbolizing that while he is becoming a better pianist he is still never as good as Keller is. Paul's desire to play at the grand parallels his desire to know more about Keller's past. When he does play the grand when Keller is not there, Paul notices the pictures of Keller's wife and son, gaining an insight into the life of his teacher. Keller's piano also symbolizes how for him music has become a refuge from the tragedies of the world. This is shown when Keller hides under his piano during the cyclone, and the piano shields him from the disaster.
Love and sexuality
Paul's sexual maturity is one of the key parts of making this novel a coming-of-age story. He experiences his first sexual feelings after meeting Megan, and his crush on her begins to consume his thoughts. Seeing the couple have sex in the library erases his interest in finding out more information about Keller. His switch from viewing Rosie as an awkward, annoying new girl to an object of desire shows his changing perspective and sexual development. He and Rosie share their first sexual experience, and Paul begins to think constantly of love and sex. When Paul finally has sex with Megan but finds it disappointing and is afraid of losing Rosie, he learns the difference between love and lust. Paul's budding sexuality often leads him to prioritize spending time with Rosie over Keller, particularly during his final night in Darwin where Keller tries to tell Paul about his past, but Paul leaves to be with Rosie.
The quest for perfection
Paul's piano studies are a quest for perfection. This is partly motivated by Paul's father's wish that his son become a much better musician than he was. It is also motivated by Keller's desire to train Paul as he would have his son, to teach him to be the best and avoid his own mistakes. Moreover, most notably, Paul strives for perfection for himself. He trains intensely with Keller and does not want to give up even when his parents have conceited that their son will be a great musician. He gives up his study of law to focus again on piano, and becomes cocky in his talents. He embarks on his two years of traveling and competing in hopes of proving himself the perfect pianist. Nevertheless, Paul ultimately falls short in his quest for perfection. He achieves mediocre results in the competition, and instead of becoming a concert pianist, he becomes a piano teacher at a middle-rate school. As Keller said, the difference between a good pianist and a great pianist is very little, and Paul is unable to achieve that extra little. At the end of the novel, Paul realizes that Keller was a much better pianist than he will ever be. He describes his quest for perfection by saying that Keller revealed perfection to him, and at the same time snatched it away.
Teaching and learning
Much of the novel focuses on the relationship between the student (Paul) and the teacher (Keller) and how the two affect one another. Initially hesitant toward the old man and his strange ways, Paul ends up learning so much from Keller about both piano and life. The teacher is initially reserved toward his student but grows to love and care for him more and more. He wants to see his student succeed in both piano and in life, and desires to share his knowledge with him so that he will learn from Keller's experiences. Paul absorbs his teacher's instructions to the point that they become dogma that he refuses to change for other instructors. Paul also forms a teacher-student relationship with some of his friends, repeating Keller's philosophies to Rosie and using his musical knowledge to teach the members of Rough Stuff how to become better musicians.
Guilt and regret
Keller's guilt over the loss of his wife and son and being unable to save them is a driving factor in his life. Because of his guilt and regret, Keller erases his former identity and goes into self-imposed exile in Darwin. He renounces the emotional music he loved the most and amputates his little finger to prevent himself from playing the instrument that he was playing while his wife and son were captured. Although the Crabbes and the Wallaces try to feed him German and Austrian food and talk to him about his homeland, his anger and regret over what happened there makes him say that nothing could ever make him homesick. Paul also experiences his own form of regret for not spending more time with Keller. In hindsight, he wishes he had not given into the temptation to spend time with his girlfriend instead of with Keller. He wishes he had written to and visited Keller more and spent more time learning from his maestro before it was too late.
Escapism
Isolated, remote Darwin is a place of escape in the novel. Keller moves there to escape from his past in Vienna and his grief and regret over the murder of his wife and son. Others come to Darwin to escape as well. Paul's father calls it a town of drunks, saying the people that come to Darwin are those who are running away to the point where they have nowhere else to go. Keller also seeks an escape through alcohol, frequently drinking schnapps. This is especially apparent when he drinks a large quantity of schnapps while trying to tell Paul the story about his wife and son. Paul also experiences the desire to escape when he tries to escape from the bullies at school. At the end of the novel he trying to escape from both the realization that he is not the successful man he wanted to be and the pain of having lost Keller.
