Unix in a Nutshell
I gave a course for Solaris users about basic UNIX administration some time ago. The literature for the course was Unix in a Nutshell. This is not the ideal book for a course (not my choice), but I think it is a great book for users of UNIX systems, especially Solaris. The book is refering to a older Solaris (Ver. 7) and SystemV Release4. Working with it was fun, even with newer UNIX versions. It is better targetting the audience for the Nutshell books (admins/users who already use and know their system and now want to have a reference and in-depth overview) than the Linux in a Nutshell
IMHO. The Linux version always seemed a bit confusing to me. The UNIX version fits much better to what I expect from such a book.
I will write a thorough review of the Unix in a Nutshell in my book review section of physos.org.
My current reading: “UNIX System Administration” by Æleen Frisch