So, Jessica's question:
What IS the difference between writing a dissertation and a book? I hear lots of people say that it'll take no time at all to turn their diss. into a monograph, but I also see people two, three, four years later who haven't completed the transition yet.
This is a really good question. (I'll just pass over the twinge I feel when I realize that we're coming up on five years since I finished my degree and my monograph is, well, still very much in progress. But I promise I won't get all defensive and rehearse the reasons for that again!)
First of all, there are a couple of books on the subject that I really like: William Germano's From Dissertation to Book, and Beth Luey's Revising Your Dissertation: Advice from Leading Editors. Anything sensible I have to say on the subject probably comes from one of these two sources.
Second, I should point out again that I have not written a book (though I did make it through a dissertation), so there are surely better-informed opinions out there than mine on how it works, and I hope anyone who's interested weighs in on the subject and feels free to contradict me. However, while I haven't written a book, I am pretty confident about the fact that my dissertation decidedly ISN'T one, so I'm going to comment from that perspective.
Okay. To me, what most distinguishes a dissertation from a book is that a dissertation is just a really big paper. It's a requirement - something you have to do to get a degree. And that imposes certain things upon a project that might not hurt it, but might not actually be necessary either. The purpose of a dissertation is to prove to a small group of people (your committee) that you are capable of doing research. It may do more than that, but it has to do no more than that. A book, in contrast, has a kind of internal consistency and says what you want it to say, and not just what you need it to say.
For me, there are two ways to think about how a dissertation differs from a book - one way is the kind of touchy-feely amorphous intangible psychological approach, and the other is the more practical approach. I'll start with the psychobabble and more to the more concrete stuff.
Not to get all sort of zen and mystical about it, but, again for me (YMMV), there's a kind of intangible, indescribable difference between writing something specifically for someone else, because it's assigned. Yes, in many ways writing the book is "assigned" because I have to do so to have the best shot at earning tenure. But I don't have to write a prospectus, or an outline, or drafts, and submit them to someone's red pen before I can continue. I know, I'll have to write a proposal and shop it around, and I'll have to get readers' reports, and I'll have to address the things they want changed. But it still feels different from being a grad student - in the end, it's my work, my decision, and I can walk away. Any publisher who goes so far as to offer me a contract will want to publish my work and want to work with me for their own benefit, not just mine. Is any dissertation really entirely one's own work when there's another person (or more than one) whose approval has to be earned before the project is done? Does anyone who oversees dissertations really want to read them? Do they get as much out of the process as the publisher gets out of publishing someone's book? (This is an honest question, because I don't supervise grad students, so I don't really know, but I suspect not.) In short, this is just a really long way to say that for me, the power relations underlying the writing of a dissertation mean that it is just different from a book - it just feels different. By the time you're finished with the dissertation, you're the world's expert on the subject and you can ideally, hopefully, see your graduate professors more as peers than bosses or superiors. But you have to spend the dissertating process to get to that point.
By the time you get to the book, your voice is different, and more pertinently, your audience is different. You're no longer writing for people whose job is to determine whether you've learned how to do this whole research thing, and who, as a corollary, have to read what you write, whether they want to or not. Instead, you're writing for people who have no power over your future, have no particular interest in your future, and assume that you do know what you're doing until proven otherwise. Instead, they have to be coaxed to read your work, with the promise that they'll learn something - something beyond the fact that you're qualified to be let loose in the archives on your own.
Personally, I don't think there's much of a workaround for this. No matter how much the dissertator has their eyes on a broader, future audience, no matter how strong a voice they develop, no matter how consciously they want to "write the dissertation as a book," I don't think you can avoid writing for your committee. But this doesn't mean you can't still write very good stuff, and for many people, this is probably not hard to rectify when it comes to turning the dissertation into a book (I'll come back to this in a moment).
To speak more concretely: I think that a dissertation frequently has a kind of "written by the numbers" quality - that is, you have X number of readers, and you have to satisfy each of them, and therefore you end up including material that will do so. Ideally - and maybe even most of the time - this will still result in a good product, but sometimes it's possible to read a dissertation and think, "here's the gender section, here's the ethnicity section, here's the quant section," etc. If you know the committee members, you can even identify their individual influences. (For the literary medievalists out there: might the obligatory Chaucer chapter fit this description? Is it possible to write a medieval (English) lit dissertation withOUT Chaucer?) The dissertation often feels like discrete pieces, addressing specific sub-questions, strung together in a line, rather than developed as a whole. (Copious use of sub-headings is a good symptom of this.)
A really obvious example of a difference: the whole lit review and related detritus that's mandatory for a dissertation is usually wholly unnecessary in a book. When you write a dissertation, you have to prove to your readers that you have found and addressed every piece of scholarship ever written on anything possibly relevant in any way to your subject. You write a lit review, and you include ridiculously verbose footnotes. When you write a book, in contrast, you leave this out. You don't have to prove you've read everything every 19th-century German theologian wrote about your topic, because book readers just don't care. (Unless, of course, they are dissertators writing a lit review... or someone like me, who gets kind of jazzed by historiography in the abstract. But those probably aren't sufficient reasons.) You only include the material that is absolutely, directly relevant, in a much more focused way.
Much of the stuff I've been going on about isn't very hard to change in the process from going from dissertation to book. The lit review problem? Usually cutting the first chapter of the dissertation solves it. The strung-together-individual-sections problem? Eliminate your subheadings. Make connections in the body of the text. Think about the broader point that you want all those individual pieces to make, and rewrite to make that point central to your writing. With the sections in place, it's probably not that hard to smooth everything out and tie it together more closely.
From personal experience, I'll point out that it's also possible to write a dissertation that adequately deals with the materials it addresses, and that demonstrates clearly that the author knows how to conduct research, but doesn't stand on its own as an argument that will appeal to a broader readership. It may need additional research to address a topic fully enough to say something that readers will want to know. It may be too narrow. It may not, in the end, have an argument that will sustain a book. These things don't make a dissertation bad; they just don't make it a book.
Now, I should conclude by acknowledging that there are people out there who write dissertations that look an awful lot like books, which don't need much revision at all. And maybe there are a lot of people out there who are like this; yes, an awful lot of people turn their dissertations into books, and many of them do it awfully quickly.* But I also think that there's kind of a pernicious myth out there that of COURSE you will turn your dissertation into a book, and of COURSE that's a simple process, and of COURSE everyone's dissertations are pretty much books-ready-to-go when they graduate, and what's wrong with YOU if yours isn't?? And as someone whose dissertation wasn't (and isn't) ready to send off the publishers, I may be speaking defensively, and maybe I have it wrong. But I'd like to raise the possibility that this is a myth, and that no one is best served by spending longer in grad school than they need to because they think they should be writing a book, nor should they put pressure on themselves to write a book. The dissertation is a really, really big paper. It should be a good paper, and it can be the basis of a book, and it's certainly worth keeping that in the back of your mind (e.g., publishers are not interested in 800-pp. manuscripts, so why write an 800-pp. dissertation?). But the most important thing is that it be done. Trust me, it's much more pleasant to figure out what to do with your project once you're out of grad school than when you're still in it.
*I have a theory that the people who turn their dissertations into books immediately are those whose advisors play a very big role in determining the dissertation topic, perhaps even assigning the topic; and that those who struggle a little more in moving to book form are those who really came up with and defined their dissertation topics on their own. Conversely, I also believe that the latter have an easier time defining new/subsequent projects than the former. But I may simply be projecting here.