Michael S. Heiser.  The Unseen Realm: Recovering the Supernatural Worldview of the Bible.  Bellingham, WA: Lexham Press, 2015.  See here to purchase the book.
Michael S. Heiser has an M.A. in Ancient History (with a focus on 
ancient Israel and Egyptology) from the University of Pennsylvania, as 
well as a Ph.D. in Hebrew Bible and Semitic languages from the 
University of Wisconsin-Madison, which is an academic powerhouse in 
Hebrew Bible and Semitic studies.
To provide a rough summary of the story that Heiser tells, let’s 
start with Adam and Eve.  According to Heiser, God created Adam and Eve 
to reproduce and fill the earth with people made in God’s image, 
extending the influence of God throughout the world (Genesis 1:28).  The
 Garden of Eden, where Adam and Eve were to receive revelations from 
God, was the earthy location of the divine council, God’s council of 
divine beings that is mentioned in Scripture (i.e., Psalm 82; I Kings 
22:19ff.).  In the ancient Near East, gods met or dwelt on mountains and
 in gardens, so Heiser believes that the Garden of Eden was a meeting 
place for the divine council.  Among the divine council was the serpent,
 who was part of the divine retinue, as serpents were in ancient Near 
Eastern imagery of gods, and perhaps also in Isaiah 6:2.  This serpent 
rebels against God and tempts Adam and Eve to sin, with the result that 
the serpent is cast to the underworld, as Heiser reads Genesis 2 in 
light of the rebellious beings in Isaiah 14 and Ezekiel 28.
Years later, after the Flood, human beings have failed to heed God’s 
desire for them to scatter throughout the earth and spread God’s 
influence.  They want to recapture the access to the divine council that
 Adam and Eve had, so they attempt to build a tower to the heavens, the 
Tower of Babel (Genesis 11).  God scatters the people over the face of 
the earth by confusing their languages.  As God divides up the nations, 
God assigns each nation to a particular god, who would rule the nation 
(Deuteronomy 4:19-20; 32:8-9).  Israel, however, would belong to God 
God-self.  Other gods try to thwart God’s plan to rule Israel and, in 
turn, to spread God’s influence throughout the world through Israel.  As
 they did prior to the Flood (Genesis 6), the gods mate with human 
beings and produce giant offspring, and this offspring inhabits the 
Promised Land, where God intends the Israelites to dwell.  The Israelite
 Conquest of the Promised Land is about ridding the land of this giant 
offspring, even though Heiser states that there were many Canaanites who
 were not giants.
For Heiser, the work of Jesus was about freeing the nations from the 
rule of the gods, so that God and exalted believers would rule the 
nations instead.  The gods are not eager to relinquish their reign, 
however, and that is why Christians are in a battle against 
principalities and powers (Ephesians 6:12).  The Kingdom of God is 
already and not yet.
This is the overall picture that Heiser presents, but there are other
 arguments that Heiser makes, as well.  Like a number of Christians, 
Heiser contends that there are two YHWHs in the Old Testament, one of 
them being a YHWH who appears to people in a visible form.  For Heiser, 
that particular YHWH is Jesus Christ.  Heiser states that, “in some of 
the oldest manuscripts of Jude (e.g., Alexandrinus and Vaticanus),” Jude
 5 states that Jesus led the Israelites out of Egypt at the Exodus (page
 270).
Another prominent topic in this book is Bashan and Mount Hermon, in 
the north.  Both were part of Og’s dominion.  Og was one of the Rephaim,
 an offspring of a divine-human union (Deuteronomy 3:13; Joshua 12:5).  
For Heiser, Bashan was a spiritually evil place.  Heiser regards it as a
 gate to hell, since Ugaritic literature presents Rephaim in the 
underworld, plus Bashan can mean serpent, and the serpent of Genesis 3 
was in the underworld.  I Enoch 6:1-6 states that Mount Hermon was where
 the divine beings of Genesis 6 came when they cohabited with women, 
producing the giant Nephilim.  In Jesus’ time, Mount Hermon was a 
prominent site of pagan temples, and Heiser argues that Jesus is 
alluding to it when he states, near that very site, that the gates of 
hell will not prevail against the church (Matthew 16:18).  Bashan 
appears in the context of Scriptural passages that the New Testament 
quotes (Psalm 22; Psalm 68), and Heiser deems that to be significant.  
Heiser also maintains that Bashan has eschatological significance, as he
 interprets eschatological danger from the north in reference to the 
evil spiritual forces of Bashan.  Most interestingly, Heiser speculates 
that the maligned cows of Bashan in Amos 4:1-2 are not rich women but 
rather supernatural beings!
Other fascinating topics that Heiser explores: the question of 
whether the “god of this age” who blinds people in II Corinthians 4:4 is
 Satan or God; the identity of Armageddon (for Heiser, it is not 
Megiddo!); why Paul wanted to go to Spain (Romans 15:24, 28), and how 
Isaiah 66:19 relates to that; themes from the Hebrew Bible that appear 
in the story of Pentecost (Acts 2); and how the Old Testament 
foreshadows (and does not foreshadow) Jesus.  And there are many more 
topics that Heiser discusses, not only in the text but also in the 
in-depth footnotes.
Here are some thoughts:
A.  I am slightly unclear about where Heiser believes the demons/gods, 
specifically the demons/gods who ruled the nations, came to be located. 
 Obviously, these gods started out in heaven, but does Heiser believe 
that the gods who rule the nations were cast from heaven into hell?  
Heiser believes that there are evil spirits in hell: the serpent, and 
the spirits of the giants.  But what about the gods who rule the 
nations?  My impression was that, sometimes in this book, these evil 
spirits got conflated, and that was where my confusion arose.
B.  There may be something to Heiser’s arguments about Bashan, in 
terms of Bashan being considered an evil place by ancient Israelites and
 later Jews.  I am not entirely convinced by Heiser’s argument that 
Bashan was considered a gateway to the underworld, however.  When 
Deuteronomy refers to Rephaim in Bashan, it may simply mean that there 
were giants who at one time lived in the land of Bashan, on earth, not 
that Bashan was a gateway to the Rephaim in hell.
C.  Heiser addressed questions that I have had.  For example, why 
would the ancients believe that gods dwelt on mountains, if they could 
simply climb the mountains and see that the gods were not there?  Why 
would God tell Adam and Eve to fill the earth in Genesis 1, when Genesis
 2 seems to presume that, had they not sinned, they would have stayed in
 the Garden of Eden rather than filling the earth?  Heiser’s answers 
generate more questions in my head, but he did well to address them.
D.  I am not saying this to be a heresy-hunter, but Heiser’s view on 
the divine inspiration and historicity of the Bible was rather unclear 
to me.  Heiser seemed to argue that the divine-human unions in Genesis 6
 and the Tower of Babel story in Genesis 11 were Jewish responses to 
Babylonian or Mesopotamian claims.  Does that imply that they were 
stories created during the exilic period and did not actually happen in 
history?  Heiser also appears to argue that the Bible reflects some of 
the limitations in knowledge of its time: for instance, Isaiah 66:19’s 
reference to Tarshish and Paul’s desire to go to Spain reflect ancient 
ideas about the extent of the earth.  Would Heiser treat this as an 
example of divine accommodation?
E.  Although my point in (D.) may portray Heiser as somewhat of a 
liberal, there were salient conservative elements in Heiser’s treatment 
of the Bible.  Source criticism was lacking in the book, as if the Bible
 reflected one divine authorial intent.  Heiser attempted to harmonize 
apparent contradictions (i.e., statements that appear to suggest that 
there are no other gods besides YHWH, and statements that acknowledge 
the existence of other gods).  Isaiah 53 is applied to the Davidic king,
 without much argument (page 247).  The Gospel of Mark is presumed to 
see Jesus as God-incarnate, when there are many scholars who disagree.  
Source criticism could have an impact on Heiser’s argument: is the 
Bible’s message, for example, that humans and Israel are to fill the 
world with God’s influence, when there are some exclusivist voices in 
the Hebrew Bible?  I doubt, though, that source criticism would 
overthrow every argument that Heiser makes.  Heiser’s approach may be a 
reasonable canonical way to approach the text, as Heiser implies when he
 refers to the divine inspiration of the text’s final form.  Plus, there
 is a possibility that New Testament authors and figures were influenced
 by the Old Testament themes in the manner that Heiser discusses.
F.  Heiser does well to refer to scholarly literature about Jewish 
binitarianism.  I question, though, whether Heiser’s interpretation of 
the Angel of the Lord is the only way to account for that figure.  Is 
the Angel of the Lord a second YHWH, co-eternal with the other YHWH, or 
is he simply a created being acting as God’s representative, carrying 
divine privileges and authority as God’s representative?  The view that a
 created being could represent God and carry divine prerogatives was 
present in ancient Judaism, as J.R. Daniel Kirk demonstrates in his 
book, A Man Attested by God (Eerdmans, 2016).
My questions notwithstanding, I found The Unseen Realm to be an interesting, engaging, and well-argued book.
I received a complimentary copy of this book from the publisher.  My review is honest!