Judaism as a Civilization: Toward a Reconstruction of American-Jewish Life is a work on Judaism and American Jewish life by Rabbi Mordecai M. Kaplan, the founder of Reconstructionist Judaism.

The book is Kaplan's most notable work and has influenced a number of American Jewish thinkers. Kaplan work centers around the concept that Judaism ought not to be defined as the religion of the Jews, but the sum of Jewish religion, culture, language, literature and social organization.

“...This classic work is widely considered the genesis of the Reconstructionist Movement, and remains one of the most original and stimulating contributions to modern Jewish thought.”— International Journal of Jewish Education Research

Judaism as a Civilization is widely considered the genesis of the Reconstructionist Movement, representing a watershed moment in modern Judaism. In this classic book, Mordecai Kaplan introduced a new way of looking at Judaism: as an evolving religious civilization. His approach required innovation in liturgy and ritual, elimination of obsolete customs, and adjustment in light of prevailing social, political, and cultural conditions. Kaplan felt that all Jews—traditional and liberal, religious and secular—could play a part in this; “reconstruction.”; Judaism as a Civilization, first published in 1934, remains one of the most original and thought-provoking contributions to modern Jewish thought.

Mordecai Menahem Kaplan was a rabbi, essayist and Jewish educator and the co-founder of Reconstructionist Judaism along with his son-in-law Ira Eisenstein.