Who is Marvin in the novel, ‘If I Forget Thee, O Earth … '?

Marvin is the main character, a boy in a moon colony, who sees the post-apocalypse earth for the first time during an earthrise when he is ten. The narrator tells the story through Marvin's eyes, revealing details as Marvin observes them; as a result, readers experience the shock of the ruined earth at the same time as Marvin does.