"Deduction: This word is often loosely used to refer to any kind of argument. But in logic it denotes a particular kind of reasoning, a process in which a conclusion is drawn after certain premises have been established. Provided that the premises are true, they guarantee the validity of the conclusion." The beginning of the entry for "deduction" suffices as an example of this tome's one-star quality. The turgid, passive writing does not guide by example; nor is the content accurate. Referring to a conclusion as "valid" in the context of schooling us about deductive logic is a glaring usage error: it is arguments, patterns of reasoning, that are "valid" just in case the truth of their premises guarantees the truth of their conclusions. The meandering entry for "deduction" is therefore more likely to spread a common usage error than to help an uncertain reader avoid error. The book as a whole takes a very nothing-is-right-or-wrong approach to English, but where the usage is of technical terms such as "validity," surely literacy calls for a little awareness and caution. Is that not the sort of nuance that distinguishes "usage" from mere "use," about which the Devil may care? Of course, a quick Google dive for examples of "valid conclusion" comes up with many live specimens, just as a quick scan of the dining room at Bennigan's will confirm that wearing a baseball hat to dinner is the thing to do.
For the most part a dictionary of random selection and noncommittal commentary on the various mutations and mutilations of English usage, scrupulously empirical to the point of uselessness, with bizarre normative interludes: on "Introductions," for example, the little lecture begins insipidly thus, "First impressions are as important in writing as they are in spoken encounters." Zzzz. I got this used for $10 and will be throwing it away -- thanks to the flabby writing, it takes up a lot of space for what little insight into English its Google trawling of illiterate ephemera offer. The best thing this sloppy waste will do for your usage is make you appreciate, and return to enjoy again, Fowler, Strunk and White, and those other relics of a time when good writers on usage provided real guidance.
By the way, the book does mention "hoi polloi," but only in a note on Greek plurals, silent on the increasingly common error mocked in this review's title. This is the classic example of a usage error that offends literate ears, something good writers who may not have the Greek surely want to prevent. To bring up this phrase in a "guide" to English usage without mentioning the degenerate version exemplifies the book's lack of focus and priorities.