Every time I write back cover copy, log lines, or any kind of summary of my work, I’m reminded of an old anime – I think it was Record of Lodoss War – that started out with a few minutes of exposition about the background. That is, more than 10% of the 22-minute episode was storytime.
Over the course of the series, the opening monologue became shorter and shorter, more and more concentrated. The joke among my friends at the time was that eventually the whole thing would boil down to “Good! Evil! Fight! Bad – BOOOOOOOM!”
So I guess there is such a thing as over-condensing your book. You don’t want the summary too dense for light to escape…