Some publishers will work directly with a writer -- this happens more often in non-fiction work than in fiction. If you do choose to work directly with a publisher, you will need to be prepared to do your own negotiation. And, you'll be involved more completely in the production of your book. Just like writers, publishers come in all flavors and sizes. So you'll want to find out what the publisher requires, that their services include (printing? promotion? distribution?). And you'll want to understand clearly what will be expected of you in the process. Today even the larger publishers expect that a writer has done his/her homework -- knows their market and is prepared to take an active role in the marketing efforts that are needed to catapult the book to success.
1st Books (Print on Demand)
Booklocker (eBooks and Print on Demand)
Bookpublisher (Print on Demand Plus Branding, Distribution & Marketing like a Traditional Publisher)
Global Book Publisher (Print on Demand - Substantial Author Discounts and Royalties)
Lumina Press -- Self-Publishing Options