This is a book I might have grown very attached to if I’d read it at nine or ten years of age. In those days, I would have glommed on to the brainy Daddy’s-girl main character and enjoyed the vaguely mythical shape of the story (3-Fates-like grandma figures and all), despite the fact that the book’s too short to indulge in much detailed world-building. A few years later, I would definitely have enjoyed the presence of the irritating but too-cute baby brother, although my own does not have dramatic mind-reading capabilities, as far as I know. As an adult, I am bothered by the fact that it’s too Christian and too American for my tastes; as a child, that probably would have passed muster with me, since I was far less judgmental and disenchanted in those days.
The emotional centre of this novel is that ghastly moment in each child’s life when they (we) discover that a parent they idolize is human and grossly fallible. It's very distressing, as a child, to find out that adults are impotent in the face of the world's overwhelming evils. The solution to the overwhelming evil in this book - simply and quite impressively named IT - is one that is cliche'd in literature, theology and popular song: love conquers everything. I've read and heard it too many times to find any sense or comfort in it (again, my 9-year-old self would probably have reacted more favourably.) However, it was quite an enjoyable short read, and I can completely understand how if someone read it in their formative years they would cling to it as a favourite book. Within a clear and straightforward narrative, it addresses a lot of the knotty philosophical questions that bubble to the surface of a thoughtful child's mind.
Besides, it's enormously helpful in understanding the concept of warp drive in Star Trek!
Christian and American biases notwithstanding, I would give this as a gift to a child without hesitation - particularly if she were a brainy Daddy's-girl.