As you move through the reading lists of brewing books available (it is pretty big if you haven't noticed) you will run into a few books that fall into the category of referrence, which can be useful for both homebrewers and pro brewers alike. A Handbook of Basic Brewing Calculations is such a book. The book comes from the Master Brewers Association of the Americas, so it is intended as a pro reference. But then the calculations are just as suitable for an advanced home brewer's brewery.
For the brewing enthusiast the book is a veritable treasure trove of useful information. Granted, the book does read like a math textbook, there is still quite a bit of information that is written in plain "brewer's english" (picture legalese... lawyers can read it but the common man has no clue).
As is common with books like this (super technical) it is not a cheap buy. Ringing in at $49 for roughly 100 pages. If you are lucky you might find it at a college library (Michigan has MEL or Michigan's Electronic Library allowing residents to check books out from most libraries in the state), although you may find that it is an essential part of your collection and the price really is worth it.
Time for a pint...