Linux+ Guide to Linux Certification, Second Edition offers the most up-to-date information which empowers students to successfully pass CompTIA's Linux+ Certification exam.
I've used a ton of resources, including other books, to learn how to navigate through Linux distros but this one by far is the best. I also had a few misconceptions cleared up, and some gaps filled in. If you are a beginner and work through this book cover to cover on an ubuntu machine, you'll gain the confidence you need to approach the Linux+ cert. I actually just borrowed this from a student, I don't want to give it back :(
Not the easiest book to read. And one warning, based on my classroom experience, most of the questions on quizzes are not directly from the book and required googling to identify what they are talking about.