Karl Hess
I once heard an interviewer describe Karl Hess as a man "whose political writing and thinking occupied at one time or another either end of the political spectrum without ever crossing the middle." I had the pleasure of meeting him when he advised the people of Hawaii on the drafting of a new state Constitution in 1977. He became friends with my uncle, a retired newspaper editor in Martinsburg, West Virginia, in the late 1980's.
This background is interesting to me, but beside my main point, which is that Hess' writing was memorable. The same interviewer asked Hess for the secret to his facility with the written word. Hess replied that he'd happily share it, because he doubted anyone would take seriously advice as simple as: "always write in the active voice."