For most of my life, whenever I read a book, I simply enjoyed it (or not) and moved on. I rarely wondered what it was about a book that I liked (or didn't), or which parts worked (or failed). But three years ago, I joined a book club and started reading books that were outside my comfort zone, more literary than the science fiction and murder mysteries that had kept me entertained for decades. The club discussions were lively, to put it mildly, but I found it very difficult to string any coherent thoughts together. I read each book carefully, but I could never find much to comment on. Some I liked well enough, and some I didn't, but I could never work out why. This gave me a vague sense of unease - it should be possible, surely, to analyse the content in more meaningful ways than: 'well, it was OK, I suppose'? The most I could ever say was that I liked such and such a character, or the prose was difficult (or easy) to read. It wasn't very satisfactory, but no one else in the group was very much better.
But then one of the club members went to some trouble to find out the background to one of the books. He looked up details of the author, her personal life, the stimulus for the story and some of the reviews. I didn't like the book any better, but it made it more interesting. So I decided to approach the problem differently. For each book, I would read reviews of it, and whatever other information I could find, before I started reading, in the hope that I would find the process more meaningful. I read reviews on Amazon, and then discovered the (better) reviews on Goodreads, and then I started getting interested.
I began, rather tentatively, to write my own reviews, and started to wonder a little about the craft of writing - about structure and pacing and character development and plot arcs and all the other technicalities. I started reading books on writing, and even dabbled a little with writing software. Not that I'm a writer, but it gave me some perspective. And I found that it all helped to focus my mind on the mechanics of a book as I was reading, so that at the end of it, I could begin to say with some confidence whether the characters (or plot or pacing) worked or not. Gradually my own reviews became more detailed, and nowadays I try to review every book I read (although the formulaic murder mysteries and cheap self-published ebooks might not merit more than a few lines - my longest reviews tend to be for fantasy).
So what goes into a review? Generally I try to comment on the first chapter; characters; writing style; pacing; plot; ending; and an overall impression. For fantasy, I'll also cover world building and magic. Having specific topics to cover ensures that the review has some structure, and also helps me to notice weaknesses (and strengths) as I read. I try to write the review as I go along, otherwise it gets a bit difficult to remember that part in chapter 7 which felt clunky or over the top. I try to mention the things I liked as well as the things I disliked, but I don't feel any obligation to 'balance' a review: if I hated a book, I'll say so.
Some people feel that a review should always be positive - the basic principle being, I suppose, that if you can't say anything good, you shouldn't say anything at all. I've even seen one poor blogger agonising over what to do when someone asks her to review a book and she really didn't like it. There's no need for such angst. Any review is just one person's opinion, neither more nor less. I have hated books that other people raved about (and vice versa, of course), so I don't feel any compunction in giving my opinion (politely, naturally).
Is there any such thing as a good book? I've waded through critically acclaimed works that I found completely unreadable, I've struggled through (and abandoned) books with strings of glowing reviews, and surely most of us have read bestsellers and emerged, puzzled, wondering just what so many millions of people saw in such tosh. So, no, I don't think there is such an animal as a 'good book'. Popular, maybe, or classic, or interesting, but 'good' is too nebulous a concept to be nailed down.
On the other hand, there may well be such a thing as a bad book. Whatever the plot or characters may be like, if it's badly written, it's a bad book. And I don't just mean using too many adverbs and cliches and other such issues beloved of the creative writing gurus - if it's ungrammatical, poorly spelled, or full of typos, it's badly written. I find, however, that grammatical errors and the like go hand in hand with poorly drawn characters and an unbelievable plot (although you still get these even with soundly constructed prose).
What is the downside of writing reviews? The main problem is that once you start analysing as you go, it becomes impossible to stop. I have heard professional writers compain about the same issue - when you are aware of writing techniques, you no longer have the ability to simply lose yourself in the story, since you're constantly noticing the clever foreshadowing, or the deftly managed rise in tension, or the subtle use of dialogue to convey character. Of course, if you do find yourself immersed in the story, that's a clear sign of a well written book. Personally, I find it's the negative aspects which tend to jerk me out of my state of disbelief - an overly hyperbolic chapter, an unbelievable plot contrivance, or an action that's out of character.
Anyone can write reviews. If you can read, you can review. All that's necessary is to give your opinion of what you liked and disliked, and (most important) to give some reason why. Even if you loved a book, it's not useful to simply say so: 'it was AWESOME!' won't help you to work out later whether to read another book by the same author, nor will it help anyone else decide whether to buy the book.
And that brings me to the other important aspect of reviews. Book-buying sites like Amazon encourage readers to add their own reviews, in the hope of making it easy for potential purchasers to decide whether or not a book is for them. There are also book-lovers' sites like Goodreads and Shelfari, with their own reviews facility. The more people who post reviews and ratings, the more information is out there and the more meaningful it is. Anyone who uses these sites regularly, and reads the reviews on them, will be aware of the number of glowing reports. If you've just read some amateurish trash, it can be quite a shock to find Amazon awash with 5 star ratings. Did so many people really love this? Or are they all friends of the author?
It can be very difficult to interpret such reviews, particularly for new or unusual books, which generally have very few. With a popular best-seller, there may be thousands of them, which gives a good statistical average of the ratings, although it can be difficult to trawl through the reviews themselves to find the most useful (useful being, in this context, those which are a reasonable length and which explain the good and bad points in some detail). But when there are only a few, it becomes more problematic, because some or all of them may not be trustworthy. So how can you tell?
Firstly, some reviewers are honest enough to confess if their opinion may be skewed. Anything that starts: 'I've known Bill for years, and this is not my usual type of reading, but hey, I thought it was brilliant...' can probably be ignored. Anyone who receives an advance review copy (ARC), or otherwise gets given a copy in exchange for a writeup, is also supposed to state this. Some reviews of this type are moderately honest, but many are from semi-professional reviewers - they may run a blog, or simply hang around discussion groups volunteering. Some get paid for their reviews, or get other inducements. The top reviewers on Amazon (yes, they have a grading system) fall into this category, and when you see how many reviews they churn out, it's obvious that they must be paid for it in some way (only the most altruistic would do all that for nothing).
But how can you tell? The FOBs (friends of Bill) are easy enough to spot. On Amazon, you can click the 'See all my reviews' link, and you will see that they've only posted a very small number of reviews. They tend to fall into the 'it was AWESOME' category, too, and may be quite short, with lots of CAPITALS and !!!!! Bear in mind, too, that these may not be FOBs at all, and may not even be real people - it's not uncommon for the author himself/herself (or agent, publisher, etc) to create a spurious account (a sockpuppet) in order to post positive reviews. The semi-professionals, on the other hand, have numerous reviews, and they're often long and superficially genuine, but they tend to follow a formula and be very upbeat, with few negatives. You don't get freebies from authors and publishers by being overly critical. Basically, any book with just a handful of glowing reviews is suspect.
Even if there are more reviews to choose from, it's not easy to spot the genuine ones. I routinely ignore both 5 star and 1 star reviews. A 3 star review is often a good guide, because no fake review would give such a low rating. If it's several paragraphs long, and makes some negative comments, even better. A reviewer who has published a number of other reviews in the same genre is also a good bet.
But however difficult it can be to find genuine information, it's still better than the good old days when the only information you had to go on was the cover and the publisher's blurb on the back. At least nowadays there is a possibility of finding unbiased reviews from people who have actually read the book. And with care, reading between the lines, it's possible to work out whether it might be the sort of book you would enjoy.