Volume Three, The Crisis of Humanism, commences with an important essay on the challenge to the humanist tradition posed in the late 19th century by historical materialism, existentialism and positivism. These Jewish thinkers of the late 19th and early 20th century addressed the general European value crisis while laying foundations for Jewish renewal: Hess, Lazarus, Cohen, Ahad Ha-Am, Dubnow, Berdiczewski, and the theorists of Yiddishism and Labor Zionism.