Here is the pdf for sale link.

http://ebooks.primisonline.com/cgi/showebook.cgi
isbn=0390684635&bookType=unselected&fulleBook=true

you may have to paste the link into one line

I've never tried the PDF myself. I think some people complained about quality though the
original has small text and low grade pictures to begin with AFAIK.

It is a superb book because it goes quite deep - so even advanced synthesists tend to find it
enlightening. It does get a bit advanced a bit quickly so I keep suspecting it might be a bit
tough for someone not too far along.

Sadly Allen Strange died earlier this year.