A pair of books from Coriolis Press about, duh, Perl. There are two flavours: the Black Book and Little Black Book. The BB covers in-depth the inner workings of the Perl API whils the LBB is a simple Language reference. I know it's probably sucideto say so, but I prefer my copy of the LBB over my "Perl in a Nutshell" -- it just seems a bit more concise, although it lacks the depth of 'Nutshell.
Name: Perl Core language - Little Black Book
Author: Steven Holzner
ISBN: 1-57610-426-5
Date Published: 1999
List Price: 24.99 USD / 36.99 CAD / 24.29 UKP