Quantum Physics is not usually a topic for light reading.  However, in this popular series, it's the bread and butter and very interesting.  The premise is based on a number of alternate realities, of which ours is the 1st or Prime reality.  Each reality is a strange take on our own with alternate versions of all the people in our reality.  The heroes use a variety of high-tech gadgets and certain people can control a power which works a bit like the Force in Star Wars.  This force congregates around people and places where great choices have taken place.

The plots are very clever, with the heroes having to solve a variety of strange riddles, which are enough to scratch the head, but not enough to hopelessly confound.  The characters are varied and interesting, and provide a constant stream of snappy dialog.  What I enjoyed most about the series thus far, was that the ideas seemed fresh, and I didn't feel like I had read it before.  The artwork accompanying the series is also intriguing, and adds to the overall appeal.

The series should appeal to a wide age group from Middle Grade to Young Adult (and, well, I liked it as a adult as well)

There is a fourth installment which comes out in 2011.  I'll be picking up my copy.