"When I start a book, I always think it's patently absurd that I can write one. No one, certainly not me, can write a book 500 pages long. (I had a hard enough time writing seven 128 page books.)
But (he goes one) I know I can write 15 pages, and if I write 15 pages every day (I'm good if it get 5-10 a day), eventually I'll have 500 of them.
John Saul, American Novelist