I believe the main themes in Looking for Alaska is growing up and self acceptance.
Throughout the book, we follow Miles’ progress in life, from leaving home to attend boarding school, to accepting his own destiny. We see him taking small and big choices, and taking the consequences of them. Miles, who earlier told himself that friendships didn’t matter, develops important friends, and learns to be dependent on them. We do also read about his heartbreaking experience of coping with Alaska’s death.
I haven’t finished the book yet, and I don’t know if my current interpretation of Miles will be the same when I have; I hope it is. I love that John Green gives Miles imperfections, these imperfections make him more three-dimensional and realistic. Even though the plot might seem extreme at first sight, John Green makes teenagers recognise themselves in Miles Halter.