Friedl's masterpiece was my introduction to server-side programming in 2000. I'd been doing front-end for a few years with Dreamweaver and I was looking-up it's find & replace features in "Dreamweaver Bible 8" where regexes were mentioned as the ultimate weapon. "Mastering Regular Expressions" was referenced in a footnote and fortunately my local library had a copy. My mind was blown. Regex symbols were just so powerful and the examples were mainly written in Perl which added even more power to them. The book was part of O'Reilly's Perl bookshelf so in addition to Friedl's book I bought the other Perl classics - "Programming Perl", "Perl Cookbook", "Mastering Algorithms with Perl" and "Learning Perl". With CPAN downloaded to my local disk I felt like a hitch-hiker setting out on a journey around the world needing nothing more than Perl in my backpack. Those were the days. Now I have to download 200Mb of node_modules before I can get started.