Mark Cahill sees only two kinds of people on earth: those who are saved and those who are lost. When he sits on a plane, walks through a mall, or strolls down a street, his passion is to establish dialog with someone to try to see which kind they are. Of course, if he discovers that the person is lost, he gently directs the discussion toward eternal concerns.

If the person is saved, Cahill tries to challenge them to also see the world as either saved or lost and obey the great commission. "Three hundred million years from now, what will be the only thing that will matter?" he asks in the introduction to his challenging book, One Thing You Can't Do In Heaven. Of course, the answer is whether you are in heaven or hell.

And the one thing you can't do in heaven is lead a sinner to Jesus. Cahill's passion for the lost has led him to devote his life to witnessing and urging other Christians to do the same. He explains that most of us neglect to witness for fear of rejection or that we do not feel prepared or qualified.

In speaking to churches and in his book, he tries to demonstrate by dozens of examples, ways to start a conversation that avoids rejection. He cites the time he approached a girl in her late teens on a beach in Florida. It was late at night and she was sitting on a newspaper stand. He started a conversation and then asked, "When you die, what do you think is on the other side?" Her interesting answer was: "A whole bunch of naked women!"

When he failed to recoil, she opened up and revealed that she was a 17-year-old Jewish girl struggling with lesbianism. She was also out beyond her curfew time because she had felt strongly impressed to come to the beach.

In the conversation, she had a lot of very in-depth questions about God and sin. Finally she said to Cahill, "You are the whole reason I came to South Beach tonight." One of her friends arrived during the discussion and she asked him what he thought about "this Jesus stuff."

Cahill says, she was witnessing and not even saved yet. Toward the end of the meeting, she asked Cahill, "Are you an angel from God?" He assured her that he couldn't be since he had an address and a phone number. "What she was saying, though, was that God had touched her life, and He happened to use me to do that," writes Cahill. "What a humbling thought that the God of this universe would use fallen mankind to plant seeds in the hearts of the lost!" They both recognized that this was a divine appointment.

Cahill's book is both challenging and instructive. The dozens of stories he shares build assurance that any Christian can and should be successful at witnessing. They also illustrate the many approaches that can be used in starting a discussion with anyone.

His book is must reading for every believer. Veteran soul winners will be encouraged to broaden their approach. Other believers will be challenged to step up to the demands of the great commission. A great discussion starter and training manual for evangelism classes.