Two great quotes on working alone:

Steve Woznikak, Apple’s co-founder:

Most inventors and engineers I’ve met are like me — they’re shy and they live in their heads. They’re almost like artists. In fact, the very best of them are artists. And artists work best alone — best outside of corporate environments, best where they can control an invention’s design without a lot of other people designing it for marketing or some other committee. I don’t believe anything really revolutionary has ever been invented by committee… I’m going to give you some advice that might be hard to take. That advice is: Work alone… Not on a committee. Not on a team. (Source)

Ernest Hemingway:

Writing, at its best, is a lonely life. Organizations for writers palliate the writer’s loneliness but I doubt if they improve his writing. He grows in public stature as he sheds his loneliness and often his work deteriorates. For he does his work alone and if he is a good enough writer he must face eternity, or the lack of it, each day.

For a true writer each book should be a new beginning where he tries again for something that is beyond attainment. He should always try for something that has never been done or that others have tried and failed. Then sometimes, with great luck, he will succeed.

How simple the writing of literature would be if it were only necessary to write in another way what has been well written. It is because we have had such great writers in the past that a writer is driven far out past where he can go, out to where no one can help him. (Source)

It’s important to note that they are advocating working alone as a means of maximizing creativity. When I first read Woz’s quote I couldn’t help but think of sole-founders in startups (of which I am one). But he’s not necessarily advocating sole-founding (after all, he cofounded Apple). He’s just saying that when creativity is an important factor in what you’re doing, you should work alone. That doesn’t mean you can’t have a co-founder though. If you do, just distance yourself when your work requires it.