Shortly before his death in 2007, in an interview for Nextbook Reader, Mailer was asked what role Judaism had played in his body of work. His response was “An enormous role.” Raised in a Jewish family, Mailer himself never accepted the traditional Judaism practiced by his parents, and (with the possible exception of The Naked and the Dead), his work does not address the lives of Jewish Americans as explicitly as some contemporary Jewish writers like Saul Bellow or Philip Roth. Yet Mailer himself insisted that the religious and spiritual aspects of Judaism as well as the experience of Jewish identity were central to his work, and this chapter provides an overview of those influences, also acknowledging how they factor into his decision to pen novels about both Jesus Christ (The Gospel According to the Son) and Adolf Hitler (The Castle in the Forest).