O'Reilly & Associates - Publishes the standard documentation for a variety of UNIX programs, such as sendmail, BIND, NFS, perl, emacs, vi, bash, csh, and more.UNIX System Administration Handbook, 2nd Edition - An excellent book which covers all aspects of UNIX administration
SAGE - The Sysadmin's Bookshelf - Books that are relevant for System Administrators
Go Solo 2 - The BookThe Complete Windows NT & UNIX System Administration Pack - The Complete Windows NT & UNIX System Administration Pack. Hewlett-Packard Education and O'Reilly & Associates have teamed up to produce the perfect toolbox for you.
