As I was researching books to read about Vietnam before traveling there, I came across The Mountains Sings. It is gripping novel, based on personal stories from family members and friends of the author. I learned a lot about Vietnam's history through this book; horrific events, hopeful moments, love for family members, and struggles to choose between loved ones. 
Absolutely read it if you're traveling to Vietnam or are interested in learning more about the history of Vietnam.