If you look at a book, usually on the dustcover, paperback cover or somewhere in the first couple of pages you will see something like "'(This author's) writing is a dazzling bravura of wild imagery and nail-biting suspense.' – Reed McReaderson" or "'A wonderful book! I couldn't put it down!' – Gush Auteur".
These little cover raves are known as "blurbs".
I am a firm believer that a handful of strong blurbs can be just as effective as the same number of positive reviews; they're shorter, they're direct, and they reveal nothing spoiler-like about the work in question. This, to my mind, makes them a good alternative for potential readers who don't want to chance having a review give away too much of the story.
Some -- but not all -- blurbs are culled from reviews. Probably half the time (or more) a writer will contact other writers and ask them if they would be willing to read something with an eye toward providing a blurb. I have gotten several wonderful quotes this way, and have also provided them for other writers. (I don't always do this; in the past 4 years I have been asked to read several novels for which, in the end, I couldn't in good conscience provide a blurb because, well...I didn't like them.)
Let me quickly address a few misconceptions about writers providing blurbs for other writers:
- Yes, a lot of the time these writers know or are at least acquainted with one another -- but that in no way means that a good blurb will be guaranteed. A writer worth any blurb value has his or her reputation to uphold, and publicly praising a bad book won't help that cause one bit.
- I can't speak for others, but I myself do read, from first page to last, each and every book I am asked to blurb. (There seems to be a rather cynical belief that writers don't bother reading their buddies' books before giving them a blurb -- while I don't doubt that this happens every so often, it is most assuredly not the norm.)
- Yes, any writer providing a blurb is aware that it's going to be used to entice a reader to buy this particular book, and will slant their blurb to that end -- but bear in mind that is because they like and believe in the book to begin with, so its integrity needn't be called into question.
This is not to say that things can't go wrong here, as well. If a book is saturated with too many blurbs, one gets the feeling that the publisher is overcompensating and perhaps trying to sell you a bill of goods. The first book in Dean Koontz's Frankenstein series has ten pages of blurbs inside.
That's overkill, because the sheer amount of them robs each individual blurb of its effectiveness. You're so numbed by the time you reach the end of the damned things you almost don't feel like reading the book -- which turns out to be quite a lot of good, old-fashioned fun. But because it starts off by pummeling you with page after page of rave blurbs (almost none of which refer to the book itself), you go in with the creeping feeling that someone is trying to convince you a sow's ear is actually a silk purse.
My own personal cutoff point is two pages or a dozen blurbs (whichever comes first); after that, I ignore them. With blurbs, less is definitely more. (The ideal for me, by the way, is a single page containing somewhere between five and ten concise, tantalizing quotes.)
I am very careful to make certain that none of the blurbs used for my books are taken out of context -- I don't want readers to feel that these quotes have been employed to mislead them, and I don't want reviewers to feel that I've misrepresented their theses by "doctoring" their comments.
What it boils down to is that strong blurbs can serve as the middle ground for readers who want some sense of what to expect from a book but don't want to chance having anything "spoiled" for them ... and reviewers can write whatever they damned well please without fear of being accused of "spoiling" anything.
I still think the best solution is to read the first few pages of a book to figure out if you're going to like it or not. But if that's not possible for whatever reason, then seek out a review; read the first two paragraphs and the last two paragraphs if you want to avoid encountering spoilers. If that doesn't appeal or work for you, then turn to the blurbs.