Forgetting the root. The emergence of Christianity from Judaism. New York: Paulist Press, 1986

Christianity was born within Judaism. How it emerged from it and finally, and irrevocably, broke with it is a long and complex story. Terrance Callan sees the process as hinging on two crucial points viz. 'first, the church's decision that Gentile Christians need not keep the Jewish law; and second, the eventual decline of Jewish membership within the church'. This is a small book packed full of scholarly information and interpretation.