As a vocabulary book, I suppose this meets the goal of having kids read the words they have just learned. The writing is simple and understandable. My kid liked it and most kids will probably also like it.
However, this is a poor retelling of the Boy Who Cried Wolf. The plot line is scattered, the parents do not discipline their children, there was no research put into depicting Medieval Europe accurately, and the dialog and internal thoughts of the characters sound like stilted caricatures instead of real conversations.
Am I demanding too much of a book that isn't meant to be a real story? Probably, but I have to get my rant out anyways. If you're a parent like me who couldn't stand it, you're not alone.