This is the sixth book in the now-famous Artemis Fowl series for children by Eoin Colfer. As suggested by its title, this book deals with time travel, setting up a situation in which the book's protagonist, Artemis, must go up against the most difficult rival yet: Uh, himself.

In the first book, child genius Artemis Fowl and the fairy people were enemies because he tried to steal their gold and kidnapped Holly. In the second book, Holly and Artemis (and the fairy people) developed a rather tenacious trust because they each helped each other. After going through technology wars in book 3, battling a megalomaniacal pixie in book 4, and getting caught up the resurgence of the demon race in book 5, it's no longer any secret that Artemis is a friend to the fairies--and his character growth has been phenomenal. By the time book six hits, Holly and Artemis would trust each other until the ends of the Earth, so it is no surprise that when Artemis hits yet another crisis, he calls Holly.

Because of some stuff that happened in the last book, Artemis is now two years younger than he "should" be, having skipped forward in time and having missed the birth of his younger brothers. His parents don't know anything's wrong only thanks to a fairy mesmer trick. But when his mother suddenly develops a mysterious illness that neither medicine nor magic can cure, Holly is more than willing to run to Artemis's side (even though she's just had a difficult mission with an exploding Kraken and whatnot). After diagnosing Artemis's mother with a fairy disease she shouldn't be able to have, they discover something very unfortunate: The only way to cure "Spelltropy" is to extract the brain fluid of a creature that is now extinct, and . . . it's extinct mainly because Artemis participated in its destruction himself when he was nine years old.

With the help of demon warlock No1, Artemis and Holly decide to go back in time and kidnap the endangered creature--a rare type of lemur--from his nine-year-old self before he sells it for money which was originally used to finance a search mission to find his father. But even though he was younger and had no knowledge about fairies as such, nine-year-old Artemis is no pushover, so present-day Artemis ends up getting basically outsmarted. (Not to mention he doesn't have the benefit of bringing his bodyguard along this time, while his younger self does have Butler--a tremendous advantage!) They again have to bring the reluctant dwarf criminal Mulch Diggums into action in order to save their butts, and after bribing him with a promise of material rewards, they have another ally. The poor lemur becomes a fought-over prize, and the two Artemises are not the only ones trying to grab it; the guy he was going to sell it to is pursuing them as well, wanting to exterminate it in an "extinctionist" demonstration for a group that dedicates itself to hating animals.

Artemis-the-Elder and Artemis-the-Younger do eventually catch on to the notion that they should probably be on the same side, and there's a lot of mess with a kidnapping, a hurtful lie, and an earlier version of a villain this group has fought before. But there's a lot to be sorted out before Holly and Artemis can return to their own time and administer the antidote . . . not the least of which is the nature of Holly and Artemis's relationship.

This book contains tons more character growth, more unexplored territory, another fantastically detailed and multi-layered plot, and of course the mandatory dozen or so flatulence-related spots of humor. (Mulch Diggums is always good for that.) I was floored by Artemis's revelations about himself (both on behalf of his younger self and his elder self); by Holly's unprecendented display of dependance during one scene when she just plain has to give up and call for help; and by the complexity of the overall plot balanced against the multi-layered feelings our protagonists have for each other. Seeing Artemis's reaction to his own dastardly manipulation of Holly's feelings--and her reaction to him when she finds out--is just breathtaking; character complexity like that is just not something you find in ordinary kids' books. The heaviness of this relationship is balanced with humor and action in a masterful way. Fans of the previous books should definitely go on to devour this volume.

Yet another code is printed at the bottoms of the pages, just like in some of the previous Artemis books. Fans of the books who have bothered to learn the Gnommish alphabet can translate and read a coded message along the bottom of each page. I of course did this. This volume contained correspondence between Opal Koboi (the pixie criminal) and Wing Commander Vinyáya, discussing whether Opal could be released since she is such a genius and her being imprisoned and unable to invent is such a disadvantage to the fairy people. The letters were amusing, involving heavy sarcasm from Vinyáya which Opal interpreted as literal statements. It ended with Opal voicing her displeasure at being tricked into thinking she was being transferred, saying she had already packed and that the packing had inadvertently destroyed two of her model seahorses made out of chewed cardboard. (I did indeed wonder if I was translating right when I got to that part, but it really does say the seahorses are made out of chewed cardboard. If you ever had any doubt that Opal Koboi is a nutcase, you have more evidence right here.)

All in all, a great read for anyone who is ready for more of these great characters and engaging plots!

Other volumes in the series: Artemis Fowl * Artemis Fowl: The Arctic Incident * Artemis Fowl: The Eternity Code * Artemis Fowl: The Opal Deception * Artemis Fowl: The Lost Colony * The Artemis Fowl Files