Building Skin on Frame Boats by Robert Morris
I actually gave mine away on this site for the price of postage to Rob. It seems to be out of print ??? and book sellers are asking a lot. But if you can find one its the best book by far. Very practical writing style with good illustrations and a much easier rib size and shape method than in Cunningham's book. Personally, I think the more books you have on any obsession the better because you can learn one simple trick that's worth a lot. In guitar making I have collections of books and they have different tricks and home made tools, jigs and fixtures. The same with skin boat building. Cunningham recommended spruce for the wood other than the ribs. I went nuts trying to find clear spruce at first and later found that people use common pine, cedar or anything and turned out perfect boats.