lists and the letter u

[SNYDER, BARRON F. (AIT)]

I'm appending string values to a list and when I print the list, the letter
'u' appears before each element:

	[u'dog', u'cat']

What does the 'u' mean? (I didn't see it documented in any of the books I
have and had a hard time searching for it in the archives)

Thanks,
Barron