In this volume, Michael O'Brien has provided both and invaluable service to parents (like myself) who want their children to read, but who are also concerned about much of the reading material currently available. He has analyzed children's literature, concentrating especially in the genre of fantasy and fairy story. He has clearly and cogently demonstrated how neo-paganism has become the dominant worldview of many authors in this genre.
Unlike many Christian authors, O'Brien has not made the mistake of throwing the baby out with the bath water. He does not lump all fantasy literature together in one category and toss it out. He carefully demonstrates the difference between good and bad fantasy literature, or, if you will, authentic and inauthentic fairy stories.
I do have a few points of contention, but they are minor, and detract very little from the overall value of the book.
1) CS Lewis is identified correctly as an Anglican -- a member of the Church of England -- but incorrectly as a member of that church's Evangelical wing. Lewis, in fact, attended a "High Church" parish, and strongly resisted political factions within churches.
2) JRR Tolkien is correctly held up as the model by which modern fantasy and fairy story should be judged. Having said this, very little actual analysis is provided for Tolkien's writings.
3) Similarly, in the book's "blurb", Charles Williams is held up -- but then not analyzed in the text. An analysis of Williams would have made O'Brien's concerns about Lewis' novel "That Hideous Strength" make more sense. (I'd still disagree with O'Brien on this one, but his case would have been stronger and easier to sensibly defend.)
4) O'Brien's analysis of Anne McCaffrey's "Pern" stories needed either to be fully developed, or eliminated entirely. O'Brien is using the image of the dragon as a neo-pagan symbol as one of the cornerstones of his book, and tries to place McCaffrey's "good dragons" within this context. To me, it was unconvincing.
Overall, an excellent book. As a final note to parents, O'Brien has helpfully added a lengthy appendix listing good (and usually available) books for children of all ages, arranged by level of difficulty and author. An extremely helpful resource for homeschooling parents.