H. Beam Piper 
Uller Uprising [EPUB ebook] 

‘ZNIDD SUDDABIT!’So the Ulleran challenge begins, with the rantings of a prophet and a seemingly incidental street riot. Only when a dose of poison lands in the governor-general’s whiskey does it become clear that the ‘geeks’ have had it up to their double-lidded eyeballs with the imperialist Terran Federation’s Chartered Uller Company. Then, overnight, war is everywhere. How it will end is in the (merely) two Terran hands of the new governor-general, a man shrewd enough to know that ‘it is easier to banish a habit of thought than a piece of knowledge.’ The problem is, the particular piece of knowledge he needs hasn’t been used in 450 years. . . .