I found this book today. The website is very plain and the information is a bit obtuse, but it is a complete 337 page book on everything you ever wanted to know about sound design and sound synthesis, although it is extremely EE/Math oriented:

The Theory and Technique of Electric Music by Miller Puckette.

If this looks (even vaguely) interesting, hop on over to Cycling74’s site. They’re the people who make SoundFlower and a whole bunch of other experimental music tools. Unfortunately, Max/MSP is stupid expensive.

Math + Computers = Music!