Joel Miller--senior editor at Nelson Current--just posted an entry called, “Book Publishing and the Market.” In it he says,
Because I have so few publishing slots, I’m supposed to be the king of cynics, the Simon Cowell of books, e.g.: “I’m sorry, but it’s really bad. Really, really bad. Honestly.” Sentiments to that effect are communicated all the time. I’m nicer than that, of course. But book proposals are many, actual slots on the list are few. My job is similar to Cowell’s; I’m supposed to filter through the many to find the few. But it’s right at this point where everything gets difficult.