For those who aren't familiar with him, Grundy is the real name of Kveldulf Gundarsson, who is the Warder of the Lore of the Troth, holds a PhD in Norse Studies, and author of numerous books popular in certain quarters of the Asatru community.
The genesis of the book is the Troth's annual gathering, where the question of Loki-worship was, and remains, a hotly debated subject. At first totally banned, then quietly tolerated in an unofficial capacity, the honoring of Loki at official Troth events has resulted in compromises that have, in general, not pleased either side of the debate. The series of articles in Idunna, and this book, were Grundy's attempt to offer an academic argument in favor of allowing the honoring of Loki in official Troth rituals and ceremonies, including Trothmoot:
An “unofficial” after-hours rite to Loki that was held at that Trothmoot  also stirred up considerable controversy, with some members feeling that their experience had been polluted, and a few opting to leave the organization. In the aftermath, long-term Troth member and scholar, Dr. Stephan Grundy, was asked to write a series of articles in The Troth’s journal Idunna reviewing the position of Loki in ancient and modern Heathenry. This book is a compilation of these articles as they were published, except for minimal editing for the sake of continuity. Dr. Grundy drew on his formidable scholarship to write them, and we hope that they are useful to the wider scholarly community— but they were written in response to a long-standing controversy within the Heathen community, and should be read in that light. (from the Preface to the book, written by Ben Waggoner, Shope of the Troth)In fairness, it should also be noted that the book does not represent official Troth policy. Nonetheless, it cannot be denied that the academic opinion of the man who holds the official position of Warder of the Lore of the Troth will certainly hold sway with many of those who do make official Troth policy. Indeed, the 2014 Trothmoot made it official policy that Loki could be honored on-site, but not in the official main ritual or sumble. The 2015 Trothmoot saw officially sanctioned Loki shrines on the site (in the same locale as those dedicated to Odin, so it was impossible to visit the latter without also being in proximity to the former). Clearly, official policy is moving towards inclusion of Loki and Lokeans, and equally clearly Grundy's book (and earlier articles) are at least partially responsible for this move in policy.
With the necessary context, background, and purpose in place, we may now proceed to the book itself.
From the outset, it is clear that any interpretation of the sources that is even slightly in favor of, or even neutral towards, Loki is the interpretation that will be used. This is, of course, a standard tactic of the Lokeans, who downplay the negatives and trumpet any positives they possibly can as far as they can:
...some have assumed that Loki’s binding in Locasenna came directly from his involvement in Baldr’s death; but that factor is neither ignored nor given any more significance than his sleeping with Sif, Týr’s wife, etc. in the poem, just as it is not even mentioned in the prose binding-account at the end.Which misses the point entirely. There does not have to be a specific reason for Loki being bound. Getting into the whys and wherefores do nothing but confuse the issue. The point is that the Aesir did bind him, specifically as a punishment, in the most agonizing form of torment they could devise. Whether they did so "merely" because of his role in Balder's death, or in sleeping with Sif, or whatever is immaterial. The Aesir, the Gods and Goddesses that are at the heart of the Asatru religion, felt justified in exiling him from their midst, imprisoning him, and subjecting him to torture until the end of the world.
Indeed, the amount of space that Grundy devotes to attacking the death of Balder as justification for Loki's banishment and imprisonment (perhaps a quarter of the whole book) could have been avoided entirely. He seems rather obsessed with the point, even though the reason is not important. The fact that it was done is what is significant. Not why.
Too, Grundy concocts some sort of long-term scheme by which it was all a part of some master plan by which Balder would survive Ragnarok in Hel, despite the fact that nothing of the sort is ever intimated anywhere in the written sources. This argument doesn't hold any water, as Balder's survival isn't ever presented as something vital to the post-Ragnarok world. Several of the Gods survive the burning of the world, and they don't need to be in Hel to do so. If Balder has some special role after Ragnarok, it's never mentioned, and thus presents no particular motive.
Chapter three presents the heart of the matter, although it sidesteps a crucial point which I'll come to. It deals specifically with the question of whether or not Loki was actually worshiped by the pre-Christian Germanic peoples.
Grundy relies primarily on the phenomenon of ritual drama, which is certainly a phenomenon whose existence can be strongly inferred. This is understandable, given the lack of evidence in place-names, literature, archaeology, or most other standard indicators of objects of cult (although it's interesting to note that he undercuts his own arguments in favor of Odin's worship (as given in his book on the subject) in his zeal to emphasize how tenuous such evidence is when used to justify cultic worship). But Grundy makes an enormous leap when he suggests that inclusion in a sacral drama is, in and of itself, evidence of worship. Indeed, he even raises a straw man argument in this regard:
To deny his importance to the practice of Norse religion in this regard, in fact, one would have to successfully present a counter-argument to Gunnell’s work on Norse ritual drama. I myself find that highly unlikely, given the huge quantity of evidence in its favour Gunnell offers.But of course no one says, let alone Gunnell, that inclusion of a particular figure in ritual drama leads to the conclusion that that figure must have been the recipient of cult. It's entirely possible to have characters, necessary to the plot and conclusion of a ritual drama, who are not otherwise included as recipients of blot, or who are not honored during sumbel. Thus, Grundy's conclusion, which appears to be grasping at straws, does not seem supported:
We can therefore say without question that he was worshipped (sic) at least in this manner.Appearing as a character in ritual drama is not the same as being worshiped. While the performance of ritual drama is, in and of itself, an act of worship, it is not the same as saying that each and every character in the drama is being worshiped. If so, then the same argument can be made for the worship of Fenrir, or Skirnir, or Thrym, or any other character who appears in the poems/dramas. The case becomes even more absurd when it is extended to the so-called heroic poems; are Atli and Fafnir and the birds who spoke to Sigurd also the objects of worship? If one takes Grundy's argument, the answer must be yes. It is (to use his own phrasing) "without question", an absurd argument.
Grundy makes a much stronger argument when it comes to post-Christian folk practices, specifically around the notion of Loki as a diminutized spirit of the hearth-fire:
It seems highly unlikely that a Norse wight generally seen as “evil” in the Heathen period would begin to receive offerings, even— perhaps especially!— simple household offerings, after the conversion.While true enough as far as it goes, it relies on two elements in the context of supporting Loki-worship; first, that the hearth-fire spirit "received offerings", and second that Loki was indeed a fire-spirit.
As to the first point, Grundy gives no evidence whatsoever, relying solely on inference. While it is true that there are folkloric references to the spirit of the hearth-fire, nowhere does he present examples of that spirit being given offerings, as would be expected if there was a practice of blot being remembered in a post-Conversion setting. Grundy couches everything in "weasel-words":
...if Loki were indeed seen as a god of hearth- and forge-fire in the Viking Age, he might have played a role in communal rituals where fires were lit. ... While this specific suggestion is no more than speculation, it seems fairly likely to me ... Loki was extremely likely to have been called on... he ... very likely [had a place] in the practice of Scandinavian worship.Everything is if, and might, and suggestion, and seems fairly likely. Nothing definitive. Just leaps to conclusions that happen to support the desired end.
As for Loki's role as a god of fire, Jan de Vries, in his comprehensive treatment of the subject of Loki, all but dismisses the possibility:
...the hypothesis of his being a fire-demon gained the greatest number of adherents. Still the evidence for this character of the god is extremely slight and the old texts are at any rate not quite explicit. (Jan de Vries, The Problem of Loki, p. 151)
The myths, where the fire-nature of Loki is accepted by the majority of scholars, are but a very frail base for such a hypothesis. (ibid, p. 161)The final part of the book deals with Loki in contemporary Heathenry, and here the knives really come out. First and foremost, yet another straw man is trotted out:
Unfortunately, to Satanize Loki and/ or to attempt to delete him from the practice and good understanding of Heathenry is to cripple our troth as a whole, both on a group level and the individual.Even the staunchest opponents of Loki-worship do not want to "delete him from the good understanding of Heathenry". Indeed, quite the opposite. A good understanding of Heathenry is one in which the ultimately negative characterization of Loki by our pre-Christian ancestors is understood and embraced, rather than modern attempts to rehabilitate him into some sort of harmless trickster or "agent of positive change through chaos". The use of the term "Satanization" is of course yet another slam at those who disagree with his position, a transparent attempt to link opposition to worship of Loki with Christianity, which understandably has a rather negative connotation within Heathen circles.
But the insults don't end there. Grundy even goes so far as to say that a Thorsman who doesn't wish to include Loki in his own worship "was either wilfully ignorant of his friend-god’s tales to a spectacular degree, or in his heart thought that his fulltrúi was an idiot."
So, disagree with Grundy and you are willfully ignorant. Charming.
Grundy makes much of the fact that many of the myths of the Gods and Goddesses for which we do have evidence of cultic activity are sometimes ambiguous. So, since Odin is a morally ambiguous figure who was nonetheless the recipient of worship, other morally ambiguous figures should also be worthy of such worship:
It seems clear to me, therefore, that Loki’s position in modern worship is, and most likely in historical worship was, similar to that of the other gods and goddesses: honoured for his help in the manners most fitting to his being; either feared or accepted for his dangers (which every deity has, from the obvious perils of Óðinn and Frigg’s impressive capacity for dirty tricks, to the terrible glaring eyes that Thórr shares with the undead and the worst seiðr-workers, to the many unnatural/ sacrificial deaths that Freyr and Freyja visited on the Yngling line); but seldom reviled.Once again, he overlooks the fact that none of those other figures are presented as being completely repudiated, exiled, and doomed to torment by the entirety of the Aesir. None of those other figures are explicitly said to aid the enemies of the Aesir at Ragnarok (as Loki is, by steering the ship Nagalfar, filled with the enemies of the Gods). As usual in this particular work, Grundy ignores sources when they speak against the point he is inexorably pushing, and holds those same sources up on high when he can twist their words to support him.
In conclusion, Grundy's book does not make the case it claims to. It is biased towards a particular outcome from the very start, takes the most advantageous interpretation of evidence it possibly can at every turn, ignores plain evidence in favor of tortured interpretations, personally smears those who disagree with the premise of the book, and relies mostly on the author's position, rather than his arguments, to make the case.
This is not a work of academic exploration. It is a hit-piece designed to promote a specific agenda, perpetrated by the Warder of the Lore to move the official policy of the Troth as an organization. As such, it has succeeded incrementally since the original articles were published in Idunna, and I have every confidence that the Troth will continue to do so, and this shabby work will be cited as justification.
If you're a Lokean, you'll enjoy this book because it supports your preconceptions. If you're interested in an academic treatment of Heathenry, this is a book that is sure to disappoint on just about every level.