I believe this book to be a gem. It is concise and funny and has a lot of valuable advice on how to be a better listener and speaker. I was left with the impression that Johnson takes semantics quite seriously but doesn't take himself so seriously as to write an inaccessible book on the subject.
"The most important thing to know about an observation is that it has to be made more than once, by more than one person, before it can be entered with confidence in the ledger of fact. Truth is never private."