"-e" and "-d" switches

mosh has asked for the wisdom of the Perl Monks concerning the following question:

Hi All,
What's the differences between the two switches "-d" and "-e" :

if($cfg{'RootDir'} and not -d($cfg{'RootDir'}) )
if($cfg{'FileName'} and not -e($cfg{'FileName'}) )
[download]

What does it means those switches?

Thanks,
Mosh.