Is it relavant? Hell yeh! And beautifully written. I tend not to like learning from online docs (I find them more useful as a reference when I'm looking for a specific answer), so I read lots of techie books. I've found the camel amongst the best - it's pretty comprehensive. Its very densely written and would not be an ideal beginners book, but it sounds like you're looking for something fairly in depth.
in reply to Is Programming Perl still relevant as a reference book?
On the cost issue, I don't know how the public library system works in Finland, but here in the UK you can ask your local library to acquire specific books for you - maybe that'd be an option.