The friendship between Martin Heidegger and Karl Jaspers developed after World War I, but became strained over the intrusion of Nazism into intellectual life. These essays provide insight into the cultural, religious, and political crises facing the two philosophers and elucidate the perennial question about the moral responsibility of intellectuals. Of particular interest is an essay by Paul Tillich, published here for the first time. Alan M. Olson is Professor of Religion and Associate Professor of Philosophy at Boston University.