He travels the world speaking on a variety of subjects, and has debated his Christian faith with a number of the world's best known atheists.
One day he met bioethicist Peter Singer. "Were your parents Christians?" Singer asked. Lennox said they were. Singer said this was one of his problems with religious belief: children tended to adopt the faith of their parents. Lennox asked "Were your parents atheists?" Singer said that they were."So you adopted your parents' faith." "No," said Singer, "because atheism is not a faith. It denies faith." "Really?" said Lennox. "I thought you believed it."
People think Christians talk about faith in Christ because there is no evidence, but Christianity is an evidence-based faith, Lennox says. "The Gospels were written to provide evidence, as the beginning of Luke attests. The end of John's Gospel says 'These are written that you may believe that Jesus is the Christ, the Son of God, and that believing you may have life in His name.'"
You don't have to choose between science and God. "Statements by scientists are not always statements of science. Stephen Hawking said 'Religion is a fairy story for people afraid of the dark.' I said 'Atheism is a fairy story for people afraid of the light.'
"For an atheist, they might be missing the point, or evading the real issue." He advises Christians to ask the most important question: Suppose I could give evidence for God, would you be prepared right now to repent and trust Christ?
People often have an attitude that it is fine for you to be a Christian so long as you keep it to yourself. Lennox appeals to Christians to speak out. He points out that the verse - 1 Peter 3:15 - which says always be ready to give a defence to everyone who asks you a reason for the hope that is in you, is preceded by a verse which says "do not be afraid of their threats, nor be troubled."
Many atheists, he says, do not support the ideas of militant atheists like Dawkins. "I have many atheist friends who thank me for taking Dawkins on."
The new atheist onslaught, says Lennox, is beginning to wane - "but Dawkins et al are still wreaking havoc in the minds of young people."
He is speaking in Northern Ireland this week, before travelling to the Faroe Islands and Eastern Europe. Wish him well.