The Independent has reprinted an interview with Kurt Vonnegut that appeared in the Paris Review in 1977 (which was actually patched together by Vonnegut himself from a series of interviews conducted over the course of a decade). He mentioned that his sister was the person he wrote for:
"...every successful creative person creates with an audience of one in mind. That's the secret of artistic unity. Anybody can achieve it, if he or she will make something with only one person in mind. I didn't realise that she was the person I wrote for until after she died."
The interview also touched on his time as a PR and advertising man, and asked whether he felt this was wasting or crippling his talent. His pragmatic response:
"No. That's romance - that work of that sort damages a writer's soul. At Iowa, Dick Yates and I used to give a lecture each year on the writer and the free-enterprise system. The students hated it. We would talk about all the hack jobs writers could take in case they found themselves starving to death, or in case they wanted to accumulate enough capital to finance the writing of a book. Since publishers aren't putting money into first novels anymore, and since the magazines have died, and since television isn't buying from young freelancers anymore, and since the foundations give grants only to old poops like me, young writers are going to have to support themselves as shameless hacks. Otherwise, we are soon going to find ourselves without a contemporary literature. There is only one genuinely ghastly thing hack jobs do to writers, and that is to waste their precious time."
Still true, maybe more so, 30 years later!