Mark Gilbert works for Certainty4Eternity, an organization established to help churches share the gospel with people from a Roman Catholic background. Mark grew up as a committed Roman Catholic, but despite this did not hear the gospel until he started university. He trained as a doctor before retraining as a minister and has served in Anglican churches in Sydney since 2000. He currently works as an chaplain on the Northern Beaches of Sydney, and partners with churches to help them to reach more Roman Catholics with the gospel. Mark has published a number of books and articles to help with this task, including 'The God Who Saves', 'The Road Once Travelled', 'Stepping Out in Faith', and 'Talking With Catholics About Jesus' (a course). He has also spoken at conferences in Australia, the United States and Europe. Leonardo De Chirico is pastor of Breccia di Roma and lecturer in historical theology at the Istituto di Formazione Evangelica e Documentazione in Padova, Italy. He blogs on Vatican and Roman Catholic issues from an evangelical perspective at Vatican Files. He's director of the Reformanda Initiative, cohost of the Reformanda Initiative podcast, and author of several books, including 'A Christian's Pocket Guide to the Papacy' and 'Engaging with Thomas Aquinas'.