answer:A regular commercial book publisher does more than print copies. There is a selection process because they want a book they can sell; they make their money from book buyers and not from charging authors money. They also perform editorial functions of some sort, even though these typically don’t measure up to the rigorous standards of old. And they provide channels of distribution and (at least a little) promotion, even though, again, it’s nothing like it used to be, unless your book is expected to be a “big book” that will make bestseller lists. Much more than before, authors do most of the promotion—but selling is easier when your book is under a “real” publisher’s imprint than when it’s published by My Little Book Company. Anybody can go pay someone to turn their manuscript into a book. The author is not the best judge of a manuscript’s readiness to go to press. If you don’t think having an editor involved makes a difference, I can point you (privately) to a number of self-published books that ought to change your mind. Authors can, of course, promote and sell their own books. I know one such who has been pushing his (printed, but never edited) novel for at least 5 years, and let me tell you, this guy is a self-promoter who never lets a prospect elude him. At least three times in the past two years I’ve heard him announce that he had reached the 5000-copies mark (a significant milestone); the last time he did so, he said he was “almost” at 5000 copies. So either the total sold has been going down or he has been shamelessly rounding up. I broke down eventually and bought a copy, and it was horrible, a shuddering embarrassment. Another author I know spends every weekend driving up and down the coast (where gas is not cheap) to hold book signings in every California bookstore that’ll have her—events that she has had to schedule herself and must show up for whether anyone comes or not. And another is lucky enough to get a lot of speaking engagements where she peddles copies in an exhausting round of small-club events and sponsored dinners. Self-publishing is more respectable than it used to be, but there is still a huge risk in that you may never recover your cash outlay and you may go out there with a book that was nowhere near ready for prime time.