Question about the ethics of reviewing books...
I was invited to review a volume of essays on my area of speciality. I agreed to this, and upon reading the essays noticed that one of the contributors included me in the acknowledgements. I do remember reading this person's essay, which was sent to me out of the blue, but we have subsequently had no ongoing relationship, neither amicable nor professional. Can I still review this volume? (I don't know any of the other contributors, nor have I previously read their papers)... thanks for your thoughts!
I don't see any problem with it at all. A review is just a review; you're just letting everyone in the field know what works and what doesn't. I don't see any conflict of interest here whatsoever. If you're in doubt, though, you can always send an email to let the editor know that you'd like to take on the project, but wanted to be clear about your involvement in case it's a deal-breaker on their end. I just don't think it's worth anyone's time for you to do that.
I wouldn't see any problem with it if you were refereeing the volume, either. In that case, I'd disclose the information to the editor, but I don't see it being a problem at all. Again, there isn't really any conflict of interest here.