What is a good review?

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I read a lot of reviews preparing to teach a class about a particular book, and I enjoyed the experience of trying to reconcile all the reviews to that actual book.  They painted an odd picture, indeed.  I found myself thinking about reviews, in general, so I'm probably going to be posting bits for the next few posts.  :)

"My definition of a “good review”, along those lines, would be one where I can tell whether or not I’ll like the book, regardless of what the reviewer thought." - from comment 16

What do you think about that idea?  What's your definition of a good review (if you read them at all)?
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