There are few historical figures in memory even after 500 years, friend or foe, who were as influential as Martin Luther. In the course of 500 years Martin Luther was viewed in many different ways: Luther as a reformer, Luther as a church father of Protestantism, Luther as a champion of reason and freedom, Luther as a brave German national hero, and many other images assigned to Luther. For Catholics, Luther has long been one of the heretics par excellence, and responsible for the split of the Western Church and its consequences-at least up until today. This thinking is now over. The Catholic Luther research in the twentieth century brought a significant shift in understanding Luther. Luther is now recognized for his insights and there is a more equitable judgment on the schism. There is now more of an understanding and ecumenical spirit. Cardinal Walter Kasper carefully presents these themes in his latest work, 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.