Artemis Fowl and the Time Paradox (Artemis Fowl #6) ~ Paperback ~ Eoin Colfer

Artemis Fowl is facing his deadliest enemy yet. Himself. Artemis is no stranger to trouble. In fact, he's a magnet for it. Man-eating trolls, armed and dangerous (not to mention high-tech) fairies, flame-throwing goblins - he's seen the lot. He had decided to forego criminal activity of the magical kind. However... Now his mother is gravely ill. Artemis Fowl must travel back through time to steal the cure from the clutches of the young criminal mastermind... Artemis Fowl. That's right. With fairy ally Captain Holly Short by his side, Artemis is going back in time to do battle with himself. Let the misadventure begin.