With 2017 marking the 500th anniversary of the Reformation, on October 31, 2016, Pope Francis will take part in an ecumenical event in Lund, Sweden. Cardinal Kasper's new book, based on a lecture at Humboldt University in Berlin, emphasises how relevant Luther's message is for Christians of all denominations. Luther's message of divine mercy was his answer to his own problems and to the questions of his time, as it is now to us in our times. Cardinal Kasper explores his understanding of Martin Luther and his contributions that could not be imagined 500 years ago, but are now in the forefront of a new ecumenical spirit. Various chapters in this book speak of the end of the confessional age, Luther in the spirit on modern times, ecumenical discovery of catholicity, and an ecumenism of charity.