if your the guy who figures out how to make an entire book case out of one sheet of plywood you'll be rich!!!!!!
But seriously. Some one mentioned face frames and I feel that is the way to go. even using the birch plywood as shelf material a nice 3/4" thick and 1+1/4 (or larger) high hard wood banding on front of the shelves not only looks nice but ads a LOT of strength.