Teach Yourself Perl in 21 Days will cover the basics in the first few chapters, and then move to practical uses of Perl and in-depth discussions of more advanced topics. Later chapters will also delve into software engineering topics, with discussions of modular code and object-oriented programming. CGI will be covered in one chapter, but will not be the focus of the book. Teach Yourself Perl will rely heavily on longer working examples and code, as opposed to small snippets and code fragments. Each chapter will include two to three smaller complete examples and one major one that illustrates most of the concepts for that chapter and builds on the chapters before it.