Linux Phrasebook by Scott Granneman
After you have learned a few basics about the command line, your next educational step is to increase your "vocabulary" of Linux commands. This book is a handy tool for that purpose. It's physically small and portable, only four and a half by seven inches, but packs a lot of useful information. It's written in a conversational style (not unlike LinuxCommand.org) and covers many useful topics. The design is fairly task-oriented, so it explains what command to use for what task. Each command is explained concisely but clearly. A good value for the money.
Disclaimer: I received a review copy of this book from the publisher.