I don't have "Perl: Black Book", so this is going to be second hand information.

I know that it has a number of good reviews on Amazon. I know that some people like it. But I am personally bothered that I have never seen a top Perl programmer recommend it. I'm also bothered that the only person that I personally knew who loved it and recommended it had picked up a style that he claimed was from the Black Book which involved no error checking. Which indicates serious flaws that most readers will not notice, but which are glaring problems that raise red flags for good Perl programmers.

Asking about it in chatter, kvale turned up this review which indicates that my doubts are well-grounded.