Because of the massive number of Roman Catholics around the world (1.3 billion people!), there is a high probability that all of us have neighbours, friends, family members and colleagues who are such.
Wherever you are in the world, Roman Catholics will likely to be your next door neighbour. Many Catholics believe and behave like most Western secular people do: without any sense of God being real and true in their lives. In other words, they are not born again, regenerated Christians.
Devout Catholics may be religious, yet entangled in traditions and practices that are far from the Biblical faith. This brings wide-open evangelistic opportunities. The gospel can and must be taken to them too. We must try to enter the Roman Catholic mindset and gently challenge it with the gospel.