Bookrate = an apparently underpublicized shipping method. Basically it's very cheap. Other than that, I don't know too much about it. I have shipped DVD's and laptop drives with it though, so I don't think it's technically limited to books. Like someone said earlier, $1.13 for under 1 pound packages, and it doesn't go up all that much from there - though I would assume there is a weight maximum since it is for books or something. Good deal compared to $3.20 priority mail shipping.