There are two that I know of, of which the best one is Frank Bethwaites "High Performance Sailing". Lots of good stuff in the other sections of the Bethwaite book, but the wind section is the best.
I second the nod for Bethwaite's book. He's pretty biased toward skiffs being the best boat in the world...but there is a lot of really good information in there about wind and how to understand what is going on.
