When I started my Time Slip Tuesday series, the books I had in mind were fantasy time travel stories, the sort where there is no real explanation of how and the time travel actually works. But my choice today-- The Navel of the World, by P.J. Hoover (Children's Brains are Yummy Books, 2009, upper middle grade, 284 pages)--is a science-fiction story, in which the mechanisms of time travel and its concomitant paradoxes are rather more central than is the case with books of the fantasy sub-genre.
In The Navel of the World, Book 2 of The Forgotten Worlds (book 1 being The Emerald Tablet), a tightly-knit group of friends returns to the summer school where they had met the year before--a summer school where they had learned that they belonged to a race of telegens, whose civilization was almost a million year old. And the kids had learned that this civilization was locked in a struggle with the false gods (telegens gone bad) who were kept imprisoned in Atlantis.
That summer, Benjamin had discovered that he was implicated in an ancient prophecy. He was one of triplets, and he had to find his lost brothers, or risk the escape of the Atlantians, would-masters of humanity. So now, with the help of devices that augment the innate skills of telegens, Benjamin and his friends are off travelling from time to time to find his brothers...before too much time passes. And in the meantime there are classes to go to, typical middle-school feelings of rivalry and hormonal type stuff to deal with, and some really bad cafeteria food.
Book-wise: Having got the backstory out of the way in The Emerald Tablet, Hoover is free to give her characters more room. They come alive in this book, and the exploration of their various mental powers is more integrated into the actual story line than was the case in Book 1. And the jostlings of middle-school life that Benjamin and his friends endure are a refreshing counterpart to the extraordinary side of things, which includes a fascinating melange of places real and imagined, although the story is weighted toward the Greek mythology end of things (adding to its cross-over appeal with the Percy Jackson books).*
Time Travel-wise: Hoover uses time travel to further a plot that remains firmly fixed in the present, as opposed to it being the end in and of itself. So there is no richly immersive experience of the past here--more a five minutes at the Trojan War, meet Achilles briefly, and off they go again sort of time travelling. So I would recommend this to kids who are looking for the science fantasy adventure side of things, rather than to readers who enjoy loosing themselves in the strange differences of the past.
*although I do think that Percy Jackson fans might enjoy this series, I'd like to point out, just so as to avoid possible disappointment, that these books are, so far, devoid of bloodthirsty monsters that require heroic slaying. The adventures here are much more cerebral, involving mental, rather than physical, prowess.
Other reviews: Lori Calabrese Writes, Jen Robinson's Book Page, and The Book Muncher.
Note: I received copies of both The Emerald Tablet and The Navel of the World from the publisher to read for the Cybils Awards--thanks, Children's Brains are Yummy Books!