BTW, I do hope you'll get a few more expensive presents as well :)

A present needs not to be expensive to be very valueable. ;)

But back to the initial question: I had vibrations from my computer's fans which resulted in a very nerving noise while I was programming in Perl reducing my productivity extremely. And after I put this book (2nd edition) onto the computer case I got silence back. Therefore the book was worth every cent. ;)

Regards
McA