Respond to the review right after the introduction, or even in the introduction itself. You can use your response to the review to set up the rest of the essay. You can start by saying something like,
In his review of Frankenstein in the Quarterly Review, John William Croker asserts that Frankenstein "inculcates no lesson of conduct, manners, or morality" (309). An analysis of the theme of domestic affection and social isolation in Frankenstein shows quite the opposite.
Or,
In his review of Frankenstein published ten years after his death, P. B. Shelley observes, "[T]here is no reader...who will not feel a responsive string touched in his inmost soul" (311). A close examination of Frankenstein's theme of domestic affection and social isolation confirms Shelley's claim.And then, in a general way, you could go on in the rest of the paragraph to explain why Croker, Shelley, or whoever is wrong or right from the point of view of your theme.
