Governmentality

This is a very basic question from a Foucault noob. I'm looking for
(if such a thing exists) the most cogent and pointed passages on
governmentality, or even a good secondary intro. Not that I don't
intend to absorb Foucault into the very fiber of my being at some
point, but right now I've got a paper to finish and I think even a
cursory understanding of the concept could be very useful to me.

Thanks,

David