Monotheism, the idea that there is only one true God, is a powerful religious concept that was shaped by competing ideas and the problems they raised. Surveying New Testament writings and Jewish sources from before and after the rise of Christianity, James F. McGrath argues that even the most developed Christologies in the New Testament fit within the context of first century Jewish ‘monotheism’. In doing so, he pinpoints more precisely when the parting of ways took place over the issue of God’s oneness, and he explores philosophical ideas such as ‘creation out of nothing’, which caused Jews and Christians to develop differing concepts and definitions about God.