I loved this book. It describes the physics of sound and how sound
is produced by
various musical instruments. It's a great source for physical
modelling synthers.

The Acoustical Foundations of Music (Hardcover)
by John Backus http://www.amazon.com/gp/product/
0393090965/102-3146998-9268930 v=glance&n=283155&s=books&v=glance
sfrules

PS. Amazon offered it paired with a book by Harry Olson. He was one
of the designers of the Bell Labs Synth...