Madeline Martin 
Keeper of Hidden Books [EPUB ebook] 

A heartwarming story about the power of books to bring us together, inspired by the true story of the underground library in WWII Warsaw, by the New York Times bestselling author of The Last Bookshop In London. "All her life, Zofia has found comfort in two things: books and her best friend, Janina. But no one could have imagined the horrors of the Nazi occupation in Warsaw. As the bombs rain down and Hitler’s forces loot and destroy the city, Zofia finds that now books are also in need of saving.