Intro to Unix books

[Tigger]

Does anyone have any recommendations for good books to help one learn Unix?
Preferably one(s) written for experienced computer users rather than novices?
Thanks in advance for any suggestions.  Please reply directly to me and I'll
summarize to the list.

Greg Orman
Systems Manager                               greg at pomona.claremont.edu
Seaver Academic Computing Services            greg at pomona.bitnet
Pomona College