cheetah book question (perl newbie)

[Jean-Paul Felix]

On page 18 of the book (1st ed) there is a line which carries out a
pre-check of $_ to see if it contains the data being searched for
(somewhere?):
next unless m/^\Q$siteName:/;
On page 24 it's:
next unless m/\Q$siteName/;

I can't find out what \Q means, I assume ^ means 'beginning with', could
someone help?
(I checked my camel and llama, though I could be looking in the wrong
places).
I'm using the same thing to speed up scanning lines in a db for the
occurence of a particular string which could occur anywhere within the line
which consists of ':' separated fields.

thanks
jpf