I have learned a great deal from Paula Fredriksen, Larry Hurtado, and James McGrath about not imposing an anachronistic conception of modern “monotheism” onto Second Temple Jewish literature. Fredriksen has urged that the term “monotheism” be retired in scholarly discussion, while Hurtado and McGrath believe that it is still a useful term as long as it is defined by the ancient evidence. Basically, unlike the post-Enlightenment worldview that relegated a deistic watchmaker deity to setting creation in motion but no longer taking an active part in it, the ancient cosmos was populated with gods, goddesses, and spirits. Second Temple Jews (and Christ-followers) did not necessary deny the existence of these other divine beings, and indeed adherents of the Abrahamic religion continue to affirm other spiritual beings as angels, but to insist that Yahweh was at the top of the divine pyramid or hierarchy. Hurtado and McGrath has argued that what set Second Temple Jews (and Christ-followers) apart was their exclusive cultic worship of the God of Israel, though McGrath argues that other divine beings could be offered more limited forms of obeisance or worship while sacrifices were to be offered to Yahweh alone. Anyways, you can find a wealth of publications from Fredriksen, Hurtado, and McGrath respectively here, here, and here.
Articles on Ancient Monotheism and Christology (Fredriksen, Hurtado, McGrath)