Given that it is billed as a companion, one would expect a balanced approach to debates in Nietzsche studies, alongside informative overviews. Unfortunately, the volume suffers from two central faults which undercut its ability to achieve this. On the one hand, a number of the chapters lack philosophical substance, reading more like discursive intellectual histories. On the other hand, the more philosophically inclined essays include misrepresentative snipes at 'analytic interpreters' of Nietzsche (mostly those notably absent from the volume).
We mentoned in October why the so-called "analytic" (i.e., philosophical) interpreters are missing from the volume. Nietzsche studies has made huge progress in the last thirty years in scholarly and philosophical sophistication. With a couple of exceptions, all this is absent from this companion, which is something like a return to "the bad old days" when Nietzsche scholars didn't need to know much about philosophy or philosophical problems and could hide behind confused blather about "masks" and perspectivism-as-relativism/idealism (see, e.g., Mitchell's discerning discussion of Stern's introductory materials to the volume).
Mitchell is good on Stephen Mulhall's embarrassing hatchet job on my views (which I had planned on letting pass in silence, but I'm grateful to Mitchell for pointing out the obvious errors), and on the Straussian esotericism implicit in Robert Pippin's essay on Beyond Good and Evil; as Mitchell writes: "there is also a price that comes with seeing Nietzsche as always, rather than just sometimes, engaged in an esoteric meta-project of not just stating (albeit in suggestive and non-commital ways) his philosophical views, but always saying things for some never explicitly stated 'effects' ('what he is trying to do by saying it' [quoting Pippin]). It makes the interpretive project closer to that of trying to uncover Nietzsche's 'hidden intentions,' something which lends itself to a form of speculation unconstrained by textual evidence." Being constrained by textual evidence is hard work, of course.
I have not yet read Sebastian Gardner's essay (though plan to), which Mitchell discusses at length, and which sounds interesting, though it (unsurprisingly) reflects Gardner's Kantian predilections in reading Nietzsche, such as supposing that Nietzsche thinks there is any "guarantor of normativity." Gardner's work is always instructive, and as longtime readers will know, I've discussed it in detail here in the past.
I also agree with Mitchell's praise for Michael Forster's essay on Nietzsche on free will; although I have some disagreements with Forster on this issue, Mitchell is exactly right that it is "a fine example of the required form and standard of content for a contribution to a companion." I expect it's the one essay in the volume that will definitely get uptake in the scholarly literature going forward.
The community of Nietzsche scholars owes Dr. Mitchell a debt of gratitude for his critical eye, good philosophical judgment, and judicious assessments.