JKR: I was going by train from Manchester to London, sitting there thinking of nothing to do with writing, and the idea came out of nowhere. I could see Harry very clearly: this scrawny little boy, and it was the most physical rush of excitement -- I'd never felt that excited about anything to do with writing. I'd never had an idea that gave me such a physical response. So I'm rummaging through this bag to try and find a pen or a pencil or anything. I didn't even have an eye-liner on me, so I just had to sit and think, and for four hours -- 'cause the train was delayed -- I had all these ideas bubbling up through my head.