Most public libraries have a standing order for all novels from reputable publishers. A good example for Australian collectors might be Bryce Courtenay's first novel, 'The Power of One'. Only a couple of thousand were printed in, I think, 1989. It's quite usual for an author to hit the big time with his or her second, rather that his or her first novel. Many authors have more than one book with an agent or publisher.
Publishers are generally conservative in outlook.
They don't like taking chances with unknown authors. If the book gains favourable reviews and goes to best-seller status quickly, a second printing will be ordered in much larger quantities. Other books by the same author will be rushed into print, either by the same or different publishers. An author's first book will always be the most collectable, unless of course a later title was printed in smaller numbers than the first. The trick is in finding a good, clean copy in an unmarked dust jacket.