Many Ruby programmers use regular expressions frequently. They are an amazingly powerful tool for many different kinds of text processing. However, if not used carefully, they can also be dangerous: They may not exactly match what their writer thinks they match, and they may execute very slowly on certain inputs. This talk will help you understand regular expressions better, so that you can make good use of their amazing power while avoiding their dangerous sides. It will also discuss recent changes to Ruby in the area of regular expressions.