The fourth edition of 'Unix Unleashed' will take a different tack from previous editions and other Unix books: It is readable as though it is a series of lectures on individual topics from Unix Wizards. This different approach will take the reader through the following topics: Basic operation of the system and system administration in its simplest form: managing users and disks, starting up and shutting down the system, authenticating user connections, and administering the X Window System. Common subsystems - the typical day-to-day tasks of system administration: sharing files, providing basic web services, printing, e-mail, and backing up the system. The Unix toolset to make system administration more reliable and more powerful, and to administer more complex and important systems running on top of Unix. System administration as a profession: much work needs to be done not to do the job in a purely technical sense but in a practical, real-world sense.