Your chief vantage ground is, That you may fasten upon any position in the book you are reviewing, and treat it as principal and essential; when perhaps it is of little weight in the main argument: but, by allotting a large share of your criticism to it, the reader will naturally be led to give it a proportionate importance, and to consider the merit of the Treatise at issue upon that single question. If anybody complains that the greater and more valuable parts remain unnoticed; your answer is, That it is impossible to pay attention to all; and that your duty is rather to prevent the propagation of error, than to lavish praises upon that which, if really excellent, will work its way in the World without your help. Indeed, if the plan of your _Review_ admits of selection, you had better not meddle with Works of deep research and original speculation; such as have already attracted much notice, and cannot be treated superficially without fear of being found out. The time required for making yourself thoroughly master of the subject is so great, that you may depend upon it they will never pay for the reviewing. They are generally the fruit of long study, and of talents concentrated in the steady pursuit of one object: it is not likely therefore that you can throw much new light on a question of this nature, or even plausibly combat the Author's propositions; in the course of a few hours, which is all you can well afford to devote to them. And without accomplishing one or the other of these points; your _Review_ will gain no celebrity, and of course no good will be done. Enough has been said to give you some insight into the facilities with which your new employment abounds. I will only mention one more, because of its extensive and almost universal application to all Branches of Literature; the topic, I mean, which by the old Rhetoricians was called [Greek: _ex enantion_], That is, when a Work excels in one quality; you may blame it for not having the opposite. For instance, if the biographical sketch of a Literary Character is minute and full of anecdote; you may enlarge on the advantages of philosophical reflection, and the superior mind required to give a judicious analysis of the Opinions and Works of deceased Authors. On the contrary, if the latter method is pursued by the Biographer; you can, with equal ease, extol the lively colouring, and truth, and interest, of exact delineation and detail. This topic, you will perceive, enters into Style as well as Matter; where many virtues might be named _which are incompatible_: and whichever the Author has preferred, it will be the signal for you to launch forth on the praises of its opposite; and continually to hold up that to your Reader as the model of excellence in this species of Writing.