A book about books! When Books Went to War: The Stories that Helped Us Win World War II describes how books were specially selected, printed in small, portable formats to fit in uniform pockets, and sent with every unit during WWII — and were considered, at least to read this book, to be essential to morale.
It was very surprising to me to encounter the vast, ambitious list of books chosen for this effort. No slouchy B list, but instead classic novels, poetry, even philosophy!
The author argues that exposing all soldiers to books encouraged them to study and take advantage of the GI Bill. She does not entirely prove her point, but the extraordinary print runs (150,000 for each title) suggest that a lot of reading was done.