The text is powerful--remarkably so for a children's book. But Nicola Bayley's paintings are, if possible, even more astonishing. There is a gorgeous picture of the Great Storm-Cat and Mowzer at sea; fine, characterful pictures of Tom, Mowzer and the village of Mousehole; and among other treasures, one picture that always moves me to tears. Another reviewer said the book made them weep: I know the page they were talking about. It's where Tom and Mowzer sail back to the village, to discover that the villagers have realized they are gone, and are waiting for them.
Enough. It's a beautiful picture. Buy the book, even if you don't have kids, though you'll get far more pleasure from reading this to a child. The language is a little complex for a child under five, but you can simplify as you read. And you'll read it again and again.