I have made some minor changes to wording of the text here and there (not controversial I think; typos etc). I'll add some further comments here that the authors might want to consider.
First, the article is exceedingly comprehensive and is clearly written by experts who are fully on top of the relevant literature. The downside of this is that it may be too long and too complex for a readership that wants quick access to essential features of the phenomenon. Would it not be helpful to trim down the introductory section that precedes Contents, concentrating on basics and omitting procedural details (e.g., of how CER works, exact shock intensities and so on).
Second, the desire to be comprehensive has led, in the main body of the article, to the inclusion of quite a few complex experimental designs and theories. Although the description in each case is accurate, I was concerned that they might ask too much of a reader not already fully familiar with this line of work. For example, I think the reference to "reinstatement" in the discussion of Donegan et al will be obscure to many, as will that to "sensory preconditoning" in the section on backward blocking. The section on "maximality and additivity" was particularly hard going, as was that on Theoretical Approaches. I am hesitant to suggest that an already long article should be expanded so as to deal with these things more explicitly -- perhaps a series of separate, related, articles would be better (e.g., Blocking: Empirical Phenomena; Theories of Blocking; Retrospective Revaluation; and so on).