Teach Yourself Perl in 21 Days by Laura Lemay is sufficient for the beginner wanting to learn Perl, be it on Windows or a UNIX-based operating system. If Perl is your first programming language, then this book is a fairly good book to choose as a starting point. It teaches the basics of programming in Perl and moves quickly from that point onward.
However, while this approach introduced me to the language I found my ability to pace through the book as I normally would with other programming languages hindered by the author's organization. Unexplained code is used in almost all of the examples before you get to its respective chapter. While this approach may work for some and give cause for thinking, it gave me an unnecessary headache.
Don't get me wrong, it did teach me a good bit about Perl, it inspired me to install Debian Linux on my programming workstation, and left me to pursue Perl. Despite this, I turned to Learning Perl. I found Lemay's writing to be too verbose and the organization of the book a bit of a twister.
Overall, it can be summed up by the following pros/cons:
- Good introduction to Perl
- Independent of Operating System (Great for Windows users ready to Learn Perl and perhaps Migrate to Linux for programming purposes)
- Solid examples and references
- Covers more advanced topics later on
- Awkward structure. Things such as loops are constantly used in beginning examples without much of an explanation. If you don't' have any experience with programming, it will give you a headache. The sections on these devices come much later, and have a strange introduction as well.
- Frustrating at times when it shouldn't be (IE, having you use functions that you haven't learned, or haven't been mentioned, in an example for a particular chapter)
Additionally, I'd recommend picking up Learning Perl or using it instead. I picked up Teach Yourself Perl in 21 Days, learned what I could, and then fell in love with Learning Perl's concise, straight to the point chapters and examples (albeit with a fair amount of humor). If you're a Linux/UNIX user, you'll probably find Learning Perl a better catch, but for me, Teach Yourself Perl in 21 Days was the stepping stone to Linux and Learning Perl. Overall, I'm satisfied with my purchase.