The nearest thing Common Lisp has to a motto is the koan-like description, “the programmable programming language.” While cryptic, that description gets at the root of the biggest advantage Common Lisp still has over other languages. More than any other language, Common Lisp follows the philosophy that what's good for the language's designer is good for the language's users. Thus, when you're programming in Common Lisp, you almost never find yourself wishing the language supported some feature that would make your program easier to write, because, as you'll see throughout this book, you can just add the feature yourself.