The Darkest Hour by Barbara Erskine
I love reading in my time period -- the one in which part of my own novel-in-progress takes place. Came upon Barbara Erskine from a book club on FB that is devoted to her fans.
After reading The Darkest Hour, which moves suspensefully between contemporary times and the Battle of Britain, I'm a devoted member of her fan club.
Stayed up till 4:15 reading this 550 page tome, and enjoyed every minute.
Reputed to be Erskine's best-loved story, Lady of Hay is waiting on my table. Next up are Time's Legacy and River of Destiny.