Yesterday, as I was pouring through a publisher catalogue, I came across a book that looked interesting, but after reading the catalogue copy a couple of times, and sharing it with a co-worker, neither one of us could figure out exactly what it was about. We were able to glean that it was about a war and took place in India, but it was only after googling certain key words from the description that I stumbled upon a summary from Scholastic Asia's catalogue that made more sense.
I think we can all admit that despite the old adage, we do judge books by their covers, but that's only the first stage to actually making the decision to purchase/read the book. It's very nice that School Library journal thought it was "superlative historical fiction" or that it's been nominated for multiple State/Provincial awards, but how does that help the average person who just wants to find an interesting read?
When I make a decision about purchasing fiction, I want to know in a paragraph or less what the book is about, and I certainly don't need long-winded descriptions that rehash the entire plot without offering any of the really important details.
In a perfect world, book summaries would only be written by people who have actually read the entire book, but in the meantime, here's my suggestion: Put yourself in the reader's shoes, and think about what you would like to know about the book, and write that as simply and succinctly as possible.