Peter Sinkowitz is a little boy who lives across the street from Stargirl. She has made detailing his personal biography one of her hobbies. She snaps candid pictures of him, jots down random events, and even collects little artifacts from his life, like discarded papers. She collects all of this information in a book and one day will present it to his parents so that they can give it to him later when he will appreciate a closer look at his past.
Leo asks her why she thinks his parents aren't doing this for him, and she responds that they most likely are creating formal scrapbooks for him with his formal pictures and such, but her journal is a truer depiction of his actual life.
This project of Stargirl's helps us understand what she finds to be very important in life, and this is in being present in the moment. It is in the little day-to-day common occurrences that Stargirl finds reason to celebrate, not the typical important stuff you might find in a scrapbook. She takes the time to look around and appreciate life for all it is; she sees the extraordinary in the ordinary. She hopes that Peter will one day appreciate knowing about the extraordinary ordinariness of his youth. You know what? Shmoop does, too.