I put a fair bit of effort into my answer, and realized that I had inadvertently also written a pretty decent blog post. So in the spirit of maximizing productivity through re-use, here it is.
Here's the best book I've ever read on office politics:Related:
The Way of the Rat: A Survival Guide to Office Politics
Author: Joep Schrijvers
However: to understand the cultural anthropology of the modern office, you need to understand anthropology in general, preferably with a smattering of evolutionary psychology thrown into the mix. Human beings have built and designed some wonderful things, ranging from flint arrowheads to Michelangelo's David to the Brooklyn Bridge to particle accelerators, but we're still giant hairless apes with swollen forebrains, and despite our carefully constructed facades, that's still how we act much of the time.
And you'll never see better examples of primate dominance hierarchies than you'll find in most "modern" offices.
Thus, I recommend:
The Naked Ape : A Zoologist's Study of the Human Animal
(Good general introduction to practical anthropology)
Author: Desmond Morris
The Moral Animal: Why We Are the Way We Are
(Good general introduction to evolutionary psychology)
Author: Steven Pinker
And for more general background:
(Motion picture, 1999; director, Mike Judge)
Time allowing, it's also not a bad idea to brush up on your Von Clausewitz, Machiavelli and Sun Tzu. A little dose of Hobbes and Kant wouldn't hurt either.