George Orwell, that is. Yeah, yeah - Animal Farm, 1984, I know.
But many people don't realize that Orwell (or Eric Arthur Blair, his real name) was an even better essayist and journalist than he was a creator of fiction. He had the ability - born of native talent and long, careful effort - to convey the most complex and nuanced ideas in simple, powerful language.
You want to improve your writing? You want to wring all the mush, stale clichés and tired description out of your prose? Then read Orwell's essay Politics and the English Language. Go ahead. Do it now - you can thank me later.