Anyway, somehow, by some means, I've got the book in my hand, and I want to know: should I bother reading this?
Of course, I can't trust the reviews on the back of the book.
For one, they were placed there by the publishers, so you can imagine their level of balance. More to it, they were written by professional book reviewers, who I can only imagine are contractually bound to only utter positive statement in regards to any book that has ever fallen under their eyes.
It is obligatory that, for any book in the fantasy genre, one of the reviews on its back cover must, must, MUST say that this book will be "beloved by fans of Tolkien". I am willing to bet that this is actually codified in U.S. federal law. You must invoke Tolkien, or else how can I even be sure that this is a fantasy book -- the wizard/knight/dragon on the cover isn't enough to give it away otherwise.
Actually, if you know ahead of time that "sure to be beloved by Tolkien fans" is reviewer-speak for "is a fantasy novel", you can actually use these to get a good idea of the quality of the book by counting them.
If there is only one "Tolkien" review, then that's just obligatory for fantasy. It's like if a steampunk book has gears on the cover; it just has to be there for you to know what genre it is. It's probably a pretty good book.
If there's more than two "Tolkien" reviews, it means that reviewers could think of nothing worth saying about the book than stating its genre over and over. Don't bother reading it, or don't expect much from it.
If there are zero "Tolkien" reviews on the back cover, absolutely none, then you are either not holding a fantasy book, or you are holding a truly incredible fantasy book. It was so good, that the reviewers had to actually describe it, rather than blithely state its genre as they normally do.
I think it's also obligatory for big-name authors to lavish unending praise upon the work of any author who cajoles them in to reading his manuscript. I really suspect that they have an authorial society like the Masons and network in positive-reviewing each other's books. This is really dangerous. I see, for instance, that Neil Gaiman thinks this is one of the best books he's ever read (they all are, apparently); I think, "Hey, Neil Gaiman likes it! He wrote Coraline! That book was incredible, therefore this book must be incredible, too!" I've fallen for this several times; no such dice. For as amazing a writer as Gaiman is, he must just have really terrible taste in literature. That, or his secretary pulls out a form review from a file and he signs off on it.
So, I go to Amazon. I pull out my smartphone, I type the name of the book in to the search bar; immediately I can see the Amazon star rating.
Any book, doesn't matter.
All books have a 4.5 star review on Amazon. No matter how terrible, no matter how great, the book has 4.5 stars.
The reason that they all have 4.5 stars is much the same that they all have big-name authors and reviewers calling them "the best book ever for all time, guaranteed to take the place of Tolkien in the hearts of readers." I guess it works like this: you bought the book, you invested hours of your time in reading the book, so you are going to like the book, gosh darnnit.
These 5-star reviews are mostly worthless. Essentially, they are say the same thing, which is "I'm a very intelligent person who enjoys reading; be like me and read."
I, of course, ignore these, and go straight to the 1-star reviews. These are the absolute best way to determine if a book is good or not.
Usually, these reviews will be absolute garbage. The reviewer will write the bare minimum 20 characters, something like "This book is so terrible, I can't believe it has such high reviews. Don't read it, waste of time, I want my money back." Some of them don't even bother to spell words correctly, and you have to wonder if they are even literate enough to have an opinion on a book?
If all of the reviews are like that, I find it incredibly useful; more commending than 300 positive reviews, is the lack of any meaningful criticism.
However, sometimes there are 1 or 2 star reviews that are actually cogent. The characters are flat, the narrative structure is pretentious, the main protagonist is an immoral monster, the plot is contrived. Stuff like that.
These are the most useful reviews of all. These reviews -- intelligent, well-reasoned, explained, thoughtful, yet negative reviews, that truly explain what there is about the book that might not be enjoyable -- are the single most useful kind of review that exist for books on Amazon's website. Whether I am convinced by them or not, I can always know from these what I'm getting in to. If the main criticism is that the prose is too florid and uses big words, then I might say "Well, I like florid prose". Or if the main criticism is that the entire female population of the book exist to be sexual servants to the protagonist, I might say "Well, I don't like that sort of thing in books"; or someone else might say "Hey, I do like that sort of thing in books".
Either way, if I want to know if I will like it, these are always the first (and usually only) reviews that I read, and they are always the most useful.
What is frustrating, however, is that negative reviews on Amazon are always ranked "unhelpful". Positive reviews are always ranked "helpful". A positive review might have 305 out of 312 people find it "helpful", while a negative review might have 15 out of 33.
It doesn't matter how detailed or clearly-explained the negative review is. People don't find it "helpful".
I can only imagine, some fan of the work has read the book and liked it, is checking the Amazon page for it - I guess to absorb the praise of the thing they love - but sees *gasp* a negative review. So they click to "dislike" it, because they disagree with it; but Amazon doesn't have a "dislike" button, so they have to click "unhelpful" instead. They then go on, attempting to salvage their pride by lavishing "helpful"s on the 50+ 5-star reviews the book has received so far.
Or so I imagine.
If I wanted to raise my reviewer ranking, then it'd be very easy; I'd just find a bunch of well-loved books, pull out a thesaurus, and proceed to exhaust the synonyms for "beautiful" in a 5-star review.
So people of Amazon, "helpful" means that a review expresses an opinion in such a way that you can better decide if you will like a book or not. It does not mean that you agree with the opinion or the ranking. It does not mean that you like the opinion or ranking. It doesn't mean that you want other people to be feel the same way about the book as the reviewer. It means that it would help someone determine for themselves if this book is worth the many hours of their time that they are about to invest in to it.
And that is how I decide if I want to buy a book or not.