

Managing a Programming Project by Phillip Metzger and John Boddie. The most readable introduction to the insanely difficult task of managing a programming project that I have yet seen. I brought my copy in to work, and the waiting list to borrow it just keeps growing. Enough people have asked where they can get a copy that I've added this link.
The Perl CD-Bookshelf
from O'Reilly is all of the best O'Reilly books on Perl on one CD (plus an actual copy of
Perl in a Nutshell):
Programming Perl, 2nd ed.,
The Perl Cookbook,
Advanced Perl Programming,
Learning Perl,
and
Learning Perl on Win32 Systems.
Of them, I regard Programming Perl (a.k.a. the Camel book) and The Perl Cookbook as absolutely essential for Perl programming, and Advanced Perl Programming as certainly nice to have, so the CD-Bookshelf actually works out cheaper--not to mention being in a very nice, searchable electronic format. Of course, if you're a real geek like me, and want to be able to read the books away from the computer, you'll probably end up getting both versions....