Can someone recommend a good book, article, etc. on the subject of chocolate that will explain the uses of the different percentages of chocolate. I'm also mystified by the references to a partiocular brand (callibaut, I recall) by numbers that seem to designate different sorts of chocolate. These usually occur in the conversations among professionals. I understand the differences between unsweetened, bittersweet, semi-sweet, etc. But these estoteric pastry chef discussions are leaving me in the cocoa dust!