Dr. Lineberry was the principal of Western Guilford Middle School.[1] She was first introduced in Ender's Game.
History
SPOILER WARNING: plot details follow.
Ender's Game
Dr. Lineberry's assistant principal had the room bugged in hopes of recording Hyrum Graff conversation with Valentine Wiggin, as they both seemed to be interested in why an International Fleet colonel would have business with a 12 year old girl.[1]