Googelen

First of all, for your 'private investigations' a good start is the ISBN finder that all major search engines provide:
isbn 0596005458 at google
isbn 0596005458 at yahoo

All on-line repositories are quite useful for finding books:
http://www.uploadscout.com/UploadScout/newindex.aspx: rapidshare & megaupload index.
You could input -for instance- digital photography on that search mask, but you can as well search with
rapidshare digital.photography: google
rapidshare "digital photography": yahoo
{frsh=94} {mtch=69} {popl=33} rapidshare "digitalphotography": msnsearch
or whatever local/main search engine you may like...

Well, I'm using "digital photography", or "photoshop" query examples just to demonstrate that finding "photoshop-related" books is almost as easy as writing them (everyone and his dog is writing a photoshop book nowadays).
Yet maybe many of the friends in this room would prefer, instead of "digital photography", this kind of books?

Note, however, that the rapidshare search-examples above are JUST ONE EXAMPLE:
Rapidshare is one of many "upload repositories" where people can (and do with gusto) upload large files.
It's quick, it allows unlimited downloads, and it has some free-happy-hours in the morning. So you don't need, of course, to pay. But there are many similar repositories:
Site:rapidshare.de/ : 30 Mb max, forever but after 30 days unused the file is removed, daily download limit of 3,000 MB for hosted files
YouSendIt: 1 Giga max, after 7 days or 25 downloads (whichever occurs first) the file is automatically removed
mytempdir: 25 Mb max, 14 days * 1200 free downloads, after that only from 23.00 to 7.00.
Sendmefile: 30 Mb max, after 14 days the file is automatically removed
Megaupload: 500 Mb max (!), forever but after 30 days unused the file is removed (like rapidshare)
ultrashare.net/ : 30 Mb max, forever but after 30 days unused the file is removed (like rapidshare)
http://www.spread-it.com/ : 500Mb - Forever or after 14 days if unused
http://turboupload.com/ : 70Mb - download delay in order to show pub
http://www.4shared.com/ : 100Mb - 10Mb per file Forever or after 30 days if unused

-inurl:htm -inurl:html intitle:"index of" +("/audiobooks""/book") +(chmpdfzip) +file mp3