Written by a British mother-son writing team (the mother is an Oxford professor, the son, was 8 when they began), this is the first of a planned trilogy. The main attraction is the twisted point of view, in which the traditional heroes -- Perseus, Jason, and the like -- are cowardly, venal, and lunk-headed, while the monsters are not only noble, kind, and usually intelligent, but also are the most fleshed-out characters in the book. This is a good introduction to some famous stories, and it can be a treat for parents, too.
The book suffers from some rookie flaws: The pacing is erratic, as is the tone, which veers wildly from wide-eyed high myth to snarky anachronisms. Even more annoying are references to events that haven't happened yet. But the story is surprisingly moving, especially a mother-son relationship.