I'm about halfway through Dogs of War by Frederick Forsyth (author of Day of the Jackal). It's flat out fascinating - a complete manual of how to overthrow a small African dictatorship, going into insane levels of detail over every facet of such an operation. For research the author met with mercenaries and arms dealers, posing as an interested party in throwing a coup of New Guinea. The balls on this guy.

There's a movie with Christopher Walken that's also pretty good, though it's less interested in the actual mechanics of throwing a coup.