I can’t recommend this highly enough.
There’s really no excuse not to have this now, if you’re even slightly interested in Csound.
(Note added 2010 Apr 15) The following purchase and price information may be getting rather out of date, but I’m leaving it here for reference.
The list price is US$70, and even at Amazon it’s over $50. But Labyrinth Books has good copies back in stock for only $37.98. Of course, there will be a shipping charge (I think it’s $4 or $5). These copies include the two CDROMs. Here’s the web page from Labyrinth: http://www.labyrinthbooks.com/all_detail.aspx?isbn=9780262522618 They describe the condition as “Very Good” which means they aren’t pristine copies in shrink wrap but might show a little warehouse scuff.
So even though it might cost you $45 or so to get your hands on a copy, on the other hand, Csound is completely free. So there’s an interesting tradeoff to consider.
Somehow, I was lucky enough to get a copy from an academic bookseller for $25. There are various used copies available, but none of them super cheap. In any case if you at all serious about Csound you should have this.
Either that or fire up your computer’s printer and buy a ream of paper.
You can read all about it at http://csounds.com/book/index.html
It comes with two CDROMs which are jam packed with more book chapters, examples, reference material, and so forth. It was printed before Csound version 5 was released but the essence of the program of course is the same.