Underland Chronicles Series Novels

Gregor and the Code of Claw (Underland Chronicles 5) by Suzanne Collins
Gregor and the Marks of Secret (Underland Chronicles 4) by Suzanne Collins
Gregor and the Curse of the Warmbloods (Underland Chronicles 3) by Suzanne Collins
Gregor and the Prophecy of Bane (Underland Chronicles 2) by Suzanne Collins
Gregor the Overlander (Underland Chronicles 1) by Suzanne Collins