A theme that shows up continuously throughout the book is courage, courage to try even when you know you may fail or to go on even in the face of adversity. Percy exhibits courage throughout the entire book, whether he is battling chimeras or journeying to the underworld. He dislplays the courage that it requires to keep his companions feeling safe and ready to follow him, which is necessary if he wants to complete his quest. The quest itself would not have been granted to Percy were it not for his courageous actions at Camp Half-Blood. Therefore courage is in integral theme of this book and to the character of Percy Jackson.