In short, no.
Although the late Michael Heiser’s books were massively popular, and he had a dedicated following on social media, his books and podcasts are basically just a legitimization, using pagan sources from the Ancient Near East, of the very old story of the “angels that sinned” myth, found in 1st Century BC texts like 1 Enoch among the Dead Sea Scrolls. This is the same belief concerning the ‘sons of God and daughters of men’ mentioned in one verse in Genesis, which has been taught in colourfully illustrated Watchtower magazines by the Jehovah’s Witnesses since 1914.
The Nephilim verse
4 The Nephilim were on the earth in those days—and also afterward—when the sons of God went to the daughters of humans and had children by them. They were the heroes of old, men of renown. (Genesis 6:4)
From this verse Mike Heiser follows the same route as the Jehovah’s Witnesses, and many other literal demon-believing churches, to read that the idols “with no spirit in them” according to the Jewish prophets (Jeremiah 10:14, 51:17 etc.) do in fact have the spirits either of fallen angels or the demon offspring in the idols. The next stage from that is that consequently gods like Baal Zebun the god to which king Ahaziah prayed for healing (2 Kings 1:2) are in fact real demons.
Genesis 6:4 sticks out awkwardly from the brief narrative of the pre-flood in Genesis 6, but it clearly does parody the fallen Titan stories found in several Ancient Near East cultures. The link to ANE fall of the Titans legends is recognised by Jewish scholarship such as the JPS commentary, and by other eminent Genesis scholars such as John Walton, but note that those scholars do not take this single verse to overturn the clearly monotheistic culture of the rest of the Old Testament. The verse is set in a paragraph wholly blaming human wickedness for the flood, not mentioning angels and demons.
A fuller answer on Genesis 6:4 is found here: Who were the sons of God who married the daughters of man in Genesis 6:2-4?
Missing the irony in the prophets and psalms
Beyond the perceived key ‘event’ of the Divine Council Worldview, the Nephilim verse above, Heiser’s worldview depends on a series of readings of Old Testament allusions to polytheistic council of the gods beliefs found in surrounding ANE cultures. These verses do exist, but like so many others Michael Heiser fails to register the common use of irony, even sarcasm, when the monotheistic Jewish writers and compilers of the Old Testament stray into allusion and comment on the beliefs of their neighbours. Or to be correct, the beliefs not only of their pagan neighbours, but also of the Jewish populace, who were constantly drawn to polytheistic worship, including Asherah poles, Baals, even child sacrifice at Tophet in Gehenna, throughout the two kingdoms period.
The Old Testament does contain references to divine councils, both to actual councils of the gods (e.g. the gods die like men parody in Psalm 82:6-7) and also to God of Israel consulting with an angelic court (e.g. Micaiah’s lying spirit parody in 1 Kings 22:22), but these are usually heavily and obviously laced with sarcasm. Much like Elijah’s infamous taunt to the prophets of Baal that their god was not answering because on the toilet (1 Kings 18:27). Michael Heiser, much like Christian readers who take the divine council idea literally, fails to even consider the issue of Jewish mockery of polytheism being the dominant note throughout the Old Testament.
Related answers:
- Why did God send a lying spirit? (1 Kings 22:22)
- What does “you are gods” mean in Psalm 82:6 and John 10:34?
- Does the divine council in Psalm 89:5-7 literally exist?
So in conclusion – No. These books are not biblical. There is one God, and one Lord, Jesus Christ.