To a faculty advisory committee at a university press, an editor’s first duty might well be gatekeeping. Let in only those projects good enough to meet are standards. (And in practice, the press discovers what its standards are partly by looking at what it has already admitted.) There aren’t SATs for authors, or many other comfortingly simple ways of measuring the achievement of your new inductees. Universities admit freshmen every spring, but in at least one what that job is easier than an editor’s. There’s an application deadline, and PhD candidates can be evaluated against one other. A waiting list is readied, and decline invitations to enroll can be swiftly papered over from the second tier of candidates. When it's over, a university won’t have applications for the following year trickling in months before the next application deadline.This routine, familiar to any academic, in the antithesis of what an editor faces. Authors write for admission at any time of year, yet often with no definite plan for the date of matriculation, as it were. (“Provide me with a contract,” writes an applicant, “and finish my book in two-or-three-years.”) This makes it difficult for a publisher to budget production and marketing expenditures. Worse, however, is that an editor must judge each application more or less independently. An editor might decline your dissertation in part because it isn't nearly as strong as an entirely different project. What an editor can’t do is shelve your project for a year in order to evaluate all her submissions on prenatal care and only then choose the one that seems strongest.
An editor will occasionally pursue projects that are too expensive or too high-profile for the house. These dissertations are rarely signed up, either because the publisher draws the line at an advance beyond the house’s purse or because the author, or the author’s agent, simply decides on a larger or richer company, or a house with more academic prestige. Some editors want only books that they can’t actually land. For that matter, some authors disdain offers from the presses that want them, all the while pining for acceptance by presses that don’t.