I just checked Amazon.com now and they do not have a book on DBA for Dummies. This was not surprising to me as I know that there are only a handful of DBAs out there specifically for MySQL.
And what topics would be covered in this book? Replication, backups, security, etc... But all of these topics can be found in other MySQL books. So, why would someone write a book for DBA for Dummies? Because it would contain advance topics or a in-depth details on the topics just mentioned. For example, how do you do circular replication? Or how do you manage 25 databases?