A good introduction to a concept that has been out there for a very long time among academics. Heiser presents a popularized overview of the spiritual worldview of Scripture, some of which he goes into more scholarly detail of in his dissertation (available online). I believe some correctives to the thesis must be in order, however, and while I realize this is a popular work, I would have liked to have seen more references in the footnotes. Weaknesses include various assumptions that I believe he makes, his view of Scripture being of the more text critical school. The argument for Harmagedon as Har-Moed, which I agree with, is very underdeveloped and, I think, poorly argued. And his treatment of Psalm 82, while fascinating and plausible on a purely ANE comparative studies level, leaves out treatment of John 10:34-35, reducing it to a mere footnote due to "space constraints." I also feel that Heiser has some rather large theological blind spots, particularly in the area of anthropology, soteriology, and eschatology, that hamper his evaluation of certain texts and issues. Heiser has a tendency to present some of his ideas as if they are essentially new and previously undiscovered insights, where the truth is that this kind of discussion of the Divine Council in OT literature has been going on for decades. I think it ultimately hurts his presentation, as people are (rightly) wary of "new" theology. There is more that could be said, specifically about how Israel's role in Scripture affects Heiser's thesis. I am currently working on a thesis paper in which I hope to deal with some of these issues, so I'll reserve more detailed commentary for that. Suffice to say, I do recommend Unseen Realm, with caution and reservation, as an introduction and popularization of some observations that scholars have been making on the OT text for a very long time. Those discussions have taken place largely in academic ivory towers behind closed doors, so Unseen Realm is a welcome popular presentation. The chapter on the Angel of Yahweh is particularly brilliant, and I would recommend the book on the merit of that alone. But, as always, read with discernment.