Originally published in 1962, there is a timeless quality that makes this not-quite definable novel a YA/Children's classic. There are strong elements of fantasy and sci-fi, and the title is a reference to the author's concept of "tesseract" - not the hypercube in the geometric sense, but a way of travel that bends the space-time continuum.
Meg Murry is 14, and the oldest girl in a household of scientists, sports whizzes and geniuses, while she is less than average, and a bit of a social outcast. She is closest to her preternaturally precocious 5-year-old brother Charles Wallace, who seems to have the ability to read her mind. Her scientist father had mysteriously disappeared while working on the tesseract, and the neighbourhood is abuzz with rumours of his abandonment of the family. Enter an eccentric baglady, Mrs Whatsit, on a "dark and stormy night", and later a jock at school whom it turns out, shares kindred feelings of being a fellow misfit, Calvin O'Keefe, and the 3 children soon find themselves on a magical journey in search of Mr Murry.
Along the way, Meg learns that "like and equal are two different things" on the planet of Camaztoz, which they have tessered onto, with the help of Mrs Whatsit (much more than a baglady) and her two companions, Mrs Who and Mrs Which, where they are persuaded to accept the norm of uniformity. Perhaps the most sobering discovery for Meg is that when she does find her father, it is much less a happy occasion that she had expected: "She had found her father and he had not made everything all right. Everything kept getting worse and worse. If the long search for her father was ended, and he wasn't able to overcome all their difficulties, there was nothing to guarantee that it would all come out right in the end. There was nothing left to hope for. She was frozen, and Charles Wallace was being devoured by IT, and her omnipotent father was doing nothing." This makes it darker than a conventional children's novel, but perhaps it is the frankness of the narrative that makes this novel endearing to generations of readers, both young and old.
While the plot was engaging, I was less impressed with the writing. At pivotal moments, there seemed to be unnecessarily long exchanges between the characters to convey conflict. Also, the way Calvin bonded with Meg and her family seemed a little contrived. Not moments after meeting Meg and Charles Wallace, he exclaims at the end of that chapter: "I've never even seen your house, and I have the funniest feeling that for the first time in my life I'm going home!" These are minor complaints and I would still recommend this novel to young readers for the ideas and concepts that were so ahead of its time.