Oh, look, the beginning of a new series!

A few years ago, my eldest started reading a series of books called Beast Quest. I was very happy he was reading, and fantasy, no less - but one thing bothered the crap out of me: It didn't seem to matter to him what order he read them in. It made no sense - how could he follow the plot if he read book five before he read book three? Or book seventeen before book nine? Then I actually read a