This entertaining puzzle book, for software developers and programming hobbyists, enlightens readers about many of the amazing and surprising behaviors of regular expressions. The author presents a series of questions, each inviting readers to think at length--and indeed to try out code on their own--before turning the page for the author's discussion and solution. The code shown in this book gives attention to regular expressions themselves, but is run using the Python programming language in particular. Everything discussed can easily be adapted to other programming languages. The short book is accompanied by quirky and obliquely relevant illustrations that add character and whimsy to the text.