I like this little phrase and I think it says a lot about Foucault’s work.
I’m glad to see it being used in Security, Territory, Population.
It is of course the title of a well-known collection of his essays (now in an interesting looking second revised edition). But also for the snappy little comment at the outset of STP:
What I am doing is something that concerns philosophy, that is to say the politics of truth, for I do not see many other definitions of the word “philosophy” apart from this (STP, p. 3).