This is the second book in a classic trilogy of children's books. It's shelved in the section for the seven to thirteen set, but I'm reading it for the first time as an adult. There are some children's or young adult books I've first read as an adult I've loved without qualification. I wouldn't though put this up there with such books by Lewis Carroll, Philip Pullman, C.S. Lewis or J.K. Rowling. I don't think the writing, world-building or characters are as strong. However, I'd probably have loved these books had I first read them as a child. And for what it's worth, I liked this second book more than the first book, A Wrinkle in Time. Meg, Charles and Calvin, the children at the center of these books, did grow on me in this book. I knew going in from a friend who loves these that, like Narnia, (or even Potter for all that it's subtle) that these are Christian fiction. It's not as blatant as in Narnia, and in fact, more than two-thirds way through the trilogy, it might be more accurate to call these "theist" or Judeo-Christian than specifically Christian. There's no Aslan-like character here, though there is a cherubim in this one. (And a cool snake, Louise the Larger--L'Engle is certainly kinder to snakes than Rowling.) While I thought Lewis knocked you over the head with the religious aspects, with L'Engle--despite some Biblical quotes and angel characters--it's more a gentle tap. Although I wouldn't call Narnia sexist exactly--the girls are just as strong as the boys and Lewis is very gender-balanced--he does fall into what a friend called "gender fail" at times, while L'Engle's female characters are strong and thoroughly modern. Meg and Charles' parents are scientists--the mother holds double doctorates in biology and bacteriology. Which leads me to another aspect of the books I really appreciated--especially in contrast to C.S. Lewis. Lewis can come across as anti-science, anti-reason, anti-tech. While L'Engle doesn't play with science quite in the sophisticated ways Pullman did in His Dark Materials, she still uses it in positive ways. How can I not find it cool to read a book staring the mitochondria? And in the end, I did enjoy this enough I went on to read the next and last book in the trilogy, A Swiftly Tilting Planet, and so far am enjoying it quite a lot. For an adult, the books in the trilogy are all very fast easy reads.