I read this book too. It is a very powerful, inspiring and moving story.
On May 27, 2001, Martin & Gracia Burnham, missionaries with New Tribes Missions in the Philippines, were kidnapped by the Islamic Abu Sayaf terrorist organization. They were held as hostages for 1 year and 11 days until their rescue on June 7, 2002. Martin died in the resulting shootout. Gracia was wounded but survived. Some will say that they had no business being there in the first place and trying to convert those people. However, the love of Christ for the lost and their desire to be obedient to His Great Commission to " Go ye into all the world and preach the gospel to every creature..." ( Mark 16:15 ) constrained them to risk their lives to do so.
" I was rescued by a helicopter, but Martin with angel's wings. "
- Gracia Burnham " When men are heathen by choice, that's THEIR business. But... when men are heathen by no choice, that's OUR business! "
- New Tribes Mission: Philippines website http://www.ntm.org.ph/