Jenny Davidson has a link to this post on how best to tackle a dissertation as a route to an academic career.
I'm a feminist. Qua feminist, I feel under some sort of obligation to chase prizes. If I drop out, I feel I'm letting the side down. And I once had a psychopathic (or do I mean sociopathic?) boyfriend who had an unerring instinct for what it took to rack up points on the scoreboard. So I must rack up points on the scoreboard. My tutors, at what had once been a women's college at Oxford, may, for all I know, have had this instinct; if they did, they chose not to share. So I found out about prizes, not from a mentor, but from a psycho- (or possibly socio-) path.
On the one hand, I went in for prizes of fiendish technical difficulty that women did not normally go in for (I think because their tutors assumed that public school men would have it sewn up, why cause unnecessary angst?). And, occasionally, won. On the other hand (know what? I don't wildly want to talk about this. But I've just read Nina Power's MS of One-Dimensional Woman, so I sort of feel I ought to)-- OK, on the other hand, when I had my final exams coming up, the psycho/sociopath would turn up at the library and want endorsement in the form of coffee in the Covered Market or some such thing, when I was just trying to prepare for the fucking exam. A week before the exam I went up to London to stay in a B&B for a night so I could revise for an exam in an X-free environment, except that X wanted to be called from a phonebox. I actually don't want to think about what it would have been like if I had had a tutor or tutors to explain how the system worked, without invocation of the crying need for a double bed.
Anyway, hm. I finished my thesis (Oxford for "dissertation") in four years, and OUP offered to publish it. But I couldn't face spending any more time on the fucker.
What I would say.
Superficially, academia looks very different from commercial publishing. I think they're really sisters under the skin.
As a graduate student, I did my doctoral research in the place that had offered me money. I did not survey the field of classicists, and/or the field of philosophers, and go where I could work with someone whose work I found exciting. I did my research in a place where I'd been offered three years' funding.
In academia, at least, you can find out about interesting people working in your field, even if you can't get money to study with them. So you can probably have some kind of intellectual engagement with them anyway.
In publishing, you have no way of finding out whether there are interesting people who would be receptive to the kind of book you want to write. Because, um, duh, in academia people have to publish to get jobs - you can get some kind of idea of whether you'd like to work with someone by his/her, um, publication record. Without which s/he couldn't had got the job in the first place. But in publishing, of course, there is no requirement to have a publication record to get a job. So. Well. Hm. It' s hard to be sane.