Rab­bi Irv­ing Green­berg is a pre­em­i­nent Jew­ish thinker, the­olo­gian, activist, pres­i­dent of the J.J. Green­berg Insti­tute for the Advance­ment of Jew­ish Life, and senior schol­ar in res­i­dence at Hadar. He is the author of five books, includ­ing For the Sake of Heav­en and Earth: The New Encounter between Judaism and Chris­tian­ity (JPS, 2004).