There is a good quality scan version of it, you can search in it and it has a chapter menu so ther is a good one out there, but as you say nothing beats the original, if I could spare the cash right now I would buy it 
.
Fun fact: the existance of the scans permanently turned Ralph off the Amiga market. We are the poorer for it, as he was working on a revised edition of his book (which is still very, very relevant today).
Well done, Internet! :-(
