Apostolic, ecumenical and radical: these are the ecclesial characteristics highlighted by Gesa E. Thiessen while explaining her vision of the church. The author focuses on the meaning of each of these marks as well as on their intrinsic connections, an approach that leads her to delve deep into the history of the church, and to draw a wide span between the apostolic past and a radical perspective on the present and future ecumenical church. Apostolic and Prophetic studies the concept of apostolicity emerging in patristic theology and examines this concept as it has been developed in select Lutheran, Roman Catholic, and Anglican ecumenical documents.