The fourth in L’Engle’s quartet of first-generation “Kairos” novels, this is fantasy SF with a Christian(ish) underpinning (not allegory, more like the Space Trilogy than Narnia). Quantum physics, time travel, angels in disguise and mythical beasts all come together to weave an original story set in a society based on the events described in Genesis 6. A couple of American teenagers (twins) are sent by mistake to ancient Mesopotamia and are taken in by Noah and his family in the months leading up to the flood.
I quite liked it and it raised some interesting questions, but it’s not particularly orthodox, doctrinally. Oh, and it isn’t a book for reading with young children………If you haven’t read any of these novels before you’re probably better off starting with “A Wrinkle in Time”, the first in this series and L’Engle’s most popular and well-known novel.