The main purpose of the book is to provide solid arguments for Catholics who have left their faith to think again about their current positions and better know the arguments behind Church's teaching, particularly those related to controversial contemporary issues. It also provides arguments for practicing Catholics to speak about God with their friends and colleagues. The book is mainly addressed to college and young professionals, but other readers with intellectual interests should also benefit from it. Following the First Letter of Saint Peter, we Christians should always be ready to provide answers: "... for people who ask you the reason for the hope that you have... with courtesy and respect" (1 Peter 3:14-16).