Room, by Emma Donoghue
Room is narrated by five year-old Jack who has lived his entire life in an 11x11 room. It's impregnable and his mother has been held captive there for seven years. She's raising a remarkably well-adjusted child. Jack is bright and inquisitive and adventurous, all without knowing there's a bigger world outside the walls of their room.
Donoghue captures the outlook of Jack and Ma. Room is haunting and elegant.