What is the single most influential book every sysadmin should read?

For software developers, there are some books you must absolutely read.

What is the single most influential book every programmer should read?

How about for sysadmins? Is there a similar list of books?

The only essential I have is The Practice of System and Network Administration by Limoncelli, Hogan, et al. My first edition copy lives on my desk

Time Management for System Administrators

It may be a bit dated, but you can't learn how to properly do your job (or how not to, I forget which one) without looking into the writings of the Bastard Operator From Hell.

Edit: Here are some links

• http://bofh.ntk.net/
• http://www.theregister.co.uk/odds/bofh/