The book, A WRINKLE IN TIME, written in 1962, seems very ahead of its time. Apparently, L'Engle had studied the quantum physics connected to Einstein, Max Planck and Werner Heisenberg while she lived in rural Connecticut after leaving a life on the Broadway Stage. The readings inspired the novel and all the others after it.
I found one quote from the book which I loved:
"We look not at the things which are what you would call seen, but at the things which are not seen. For the things which are seen are temporal. but the things which are not seen are eternal."