I can't believe this book got only three stars from the CSM reviewer! This is one of the most hilarious books I have read in a long time, and it had charming friendship, a clever protagonist, world-saving heroics and lots of exciting (but not particularly scary) action. I could not put it down, and now my son can't, either!
My only small comment is that while I giggled practically every time the alien character was referred to as "J.Lo," my son, age 8, did not get this reference, and therefore saw no humor in it. A joke you have to explain is just not that funny. I am sure some kids would get the joke, but "J.Lo" is not a pop-culture reference that will reach everyone!