Total Number of Middle School Books: 3,440
Ultimate Ocean Rumble
Ultimate Reptile Rumble (Who Would Win?)
Ultimate Shark Rumble (Who Would Win?)
Una arruga en el tiempo
Unbound: A Novel in Verse
Unicorn Bowling (Phoebe and Her Unicorn Series Book 9)
Unicorn Crossing (Phoebe and Her Unicorn Series Book 5)
Unicorn Famous (Phoebe and Her Unicorn Series Book 13)
Unicorn of Many Hats (Phoebe and Her Unicorn Series Book 7)
Unicorn on a Roll
Unicorn Playlist (Phoebe and Her Unicorn Series Book 14)
Unicorn vs. Goblins (Phoebe and Her Unicorn Series Book 3)
Un libro de Mono y Pastel: ¿Qué hay en la caja? (What Is Inside This Box?)
Unnecessary Drama
Un Paseo de Compras Problemático
Unstoppable Octobia May
Unstoppable: True Stories of Amazing Bionic Animals
Vampire Crush