Mac OS X is the most significant advance in desktop computing since the introduction of the original Mac interface.
This book is a small part of a big revolution: the introduction of the Unix operating system to regular computer users. Never before have so many people had access to a common platform that is powerful, stable, and open to being reshaped through the collaborative efforts of all who contribute. Mac OS X provides a real "Mac interface" to a real Unix operating system, so if you are using Mac OS X, you're using Unix. Unix is an industrial-strength operating system specifically designed for always-on, network-connected computers that run multiple applications and are shared by many users. There are many different "flavors" of Unix and Unix-like operating systems; GNU/Linux and Mac OS X are by far the most common on desktop and laptop computers. If you have heard of Linux, it would be roughly correct to say that Mac OS X gives you everything Linux gives you, but with a Mac interface.
Since its creation in 1969, Unix has evolved into one of the world's most popular operating systems for servers and increasingly for desktop use. Moreover, Unix is an excellent environment for creating new software. Apple built Mac OS X on top of a version of Unix called Darwin. If you're a Mac user who wants to push the boundaries of what you can do with your computer, here's what Unix can do for you.