a scalar is a LISP atom...the basic unit in Perl, and you get to it via a $.
An array is a collection of scalars. This is why you have to have a reference to have a list of lists.
Likewise a hash is a collection of keys, which have to be scalars (see the Tie module if you want it to be something else) to scalars.
A Perl reference merely is a scalar to something else (such as a scalar, array or hash).
$scalarRef = \\$scalar
$listRef = \\@list
$hashRef = \\%hash
To access -
$scalar = $$scalarRef
@list = @$listRef
$hashRef = %$hashRef (iirc)