Comment Use book as ultimate reference (Score 1) 987
A few thoughts.
I once talked to someone who has written a few computer books and the input I got was that she was not getting much from the books. She mentioned that what the books did help with was stablishing yourself as a subject matter expert so you could get paid more when doing consulting/work in the field you wrote.
To that regard one possibility may be to do nothing about the pirated copies and/or let your publisher deal with it.
I also recall reading recently comments from a couple of publishers (including the owner from stardock) who basically said you loose more trying to fight pirates than by worrying only about paying customers. There will always be people willing to download some material for free that they would never be willing to pay for.