Missing mac address book!

You might be able to reinstall it from your install discs. The data should be located in ~/Library/Application Support/Address Book/ and once reinstalled it'll hopefully read that data on its own.

 

Where exactly did you look for it? Did you look in your Applications folder? Also, did you try Spotlight? (Sorry if I’m treating you overly-noobish, but some people see things disappear from their Dock and don’t know where to look next, so I’ve gotta check for that stuff before I get into more involved solutions.)

Also, do you use Time Machine? That would make it very easy to recover if it has, in fact, been lost.