These are books I often find myself recommending for non-believers to read in order to hear the gospel presented clearly and winsomely as well as have common objections answers and unbelief challenged.
Two Ways to Live Tract | Matthias Media (Very Easy). We use this simple gospel presentation for our youth. If you want to quick to the heart of the Christian’s message, this is a great place to go. There are pictures too!
Christianity Explored | Rico Tice (Easy). Short, simple, with down to earth language and style. I have a stack of these in my office ready to give out to new and non-believers alike. You can see their very good website here.
Basic Christianity | John Stott (Easy). Stott lays out the good news clearly by getting into the person of Jesus Christ, the need of Mankind for salvation, the work of Christ on the cross, and the necessary response of Man to receive salvation. Fantastic for new believers and non-believers alike.
Reason for God | Tim Keller (Medium). Keller effectively dismantles our cultures major views and objections that keep them from taking Christ seriously and does a great job presenting what Christianity is all about.
The Case for Christ | Lee Strobel (Easy to Medium). A former Chicago Tribune journalist chases down the biggest story in history–is there credible evidence that Jesus of Nazareth really is the Son of God? Put this in the hand of skeptics who watch too much History Channel.
More Than a Carpenter | Josh and Sean McDowell (Easy). Father and son do some tag-team apologetics and, in a very quick, punchy, and straight-to-the-heart way, show that Jesus indeed was more than a carpenter (you see what I did there?).