Whose Religion is Christianity? by Lamin Sanneh
A prof who has taught at Harvard and Yale, a native of Africa but thoroughly conversant with Western scholarship and literature, and a former Muslim who converted to Christianity (Roman Catholicism specifically), it's hard to see who could be better qualified to tackle this topic.
Unlike Cragg's book, this one makes for a short, easy read. He grapples with questions about colonialism, Western guilt, translation and pluralism, but does so in an easy-to-understand format of question and answer.
Especially good to read along with The Next Christendom by Philip Jenkins.
Also available at Amazon.