This is on of the later books but set early in his career. The story opens with James DiGriz, prisoner, being shipped to some planet to face charges of bank robbing, after lamenting his misfortune he escapes from the pot into the fire.
James finds himself on a military planet and promptly gets drafted. He learns a nemesis of his, formerly Captain Garth, is now General Zennor, planning an invasion of an unknown planet and is enlisted by the League Navy to identify that planet – if he can’t kill General Zennor first.
The target planet turns out to be a utopian planet with no government and practicing a philosophy of Individual Mutualism, which seems to be a rather libertarian approach to life. There is no army, no police and no problems. On such a world, how do you defeat a heavily-armed invasion force?
As usual, he goes from one problem to another finding the most unusual solutions to problems in amusing ways and finds a most unusual solution to outwitting an invading army.