Part of the question of cohrerence is how much connective tissue to lay down in an essay format. By which I mean something like this:
"What holds an essay together...should be nearly invisible. The best kind of structure should be organic, revealing only the very natural way a smart person's mind works through a topic, making connections and forming conclusions as they occur. And an essay can contain many thoughts and observations that might not seem to fit together, but in the end lead to a satisfying whole..." (Susan Orlean, Introduction, Best American Essays 2005)I might not go so far as to say I think that sort of structure makes the *best* essays, but it's certainly an essay form I enjoy, and I think the form I'm currently using. But I'm not certain how well I can make such a non-explicit form work at book length -- it requires a remarkable amount of trust on the part of the reader, that eventually all these disparate elements will come together into a coherent whole, and that trust is easier to sustain for twenty pages than two hundred. So I'm thinking about what I can give the reader in the interim, to satisfy them and maintain their trust, while all the little pieces of the big picture slowly start slotting into place.
Right now, for example, Jed is seeing two very different threads in my narrative, and not seeing any connection between them. And I'm pretty sure that the connection between them is actually the point of the book. But it's going to take maybe 'til halfway through the book for that connection to start becoming visible. Hm...
Alternately, I *could* just lay it all out at the beginning, in a kind of introduction. Foreground the philosophical basis of the exploration, just tell the reader up front what I'm going to be talking about. I could do it in three sentences. But that seems a bit painfully academic, possibly off-putting. Graceless. Though I'm sure there are books that do it beautifully. Hm...
It's much the same problem you encounter in fiction, really, balancing implicit and explicit. Generally I want to only be as explicit as I absolutely have to be -- I'd much rather imply everything in my fiction. I only explain if too many readers are too clearly confused. But nonfiction has a lot more potential room for tolerance of the explicit -- or even need for the explicit. Which gives you more options to play with, but also more room for confusion about the right balance of the two...
I should (sleepily) note a couple of things:
1. I often prefer things to be more spelled out than some other people would like. It’s fairly common for me to say, about a submission we’re considering, “I like it, but I don’t get X; I’d like that to be made clearer.” And for Karen and/or Susan to respond, “Making it clearer would ruin it; it’s plenty clear enough as it is.” So you maybe shouldn’t base too much on my opinion in this regard.
2. Re the general issue of organic essay structure (not your book in particular), I agree that that the structure Orlean describes is a good one, and I agree that it’s probably much harder to maintain for 200 pages than for 20. I’ll fall back on Ben’s “sources of reader pleasure” thing. I think ideally when I’m reading such a work, the writing, or the story, or the sharply observed details, or something else, would sweep me up and keep me so involved and interested that I wouldn’t notice or care that I wasn’t really sure along the way how the thematic parts fit together. I’m inclined to feel that that’s a good way to get the reader to trust the author that things will come together by the end–or to get them to not especially need to trust the author about that because they would enjoy the piece even if it didn’t come together in that way. Garrison Keillor’s “News from Lake Wobegon” segments, at their best, do this (though they’re fiction, so not really the same thing): his stories are sometimes very wandery, moving from one character to another through a series of apparent digressions with no immediately obvious theme, but I enjoy the journey so much that I don’t mind the apparent drift — and then at the end he brings everything back full circle to where he started, and it suddenly makes sense as a coherent whole. He doesn’t always manage this, but some of the best ones are, to me, breathtaking. (But part of what keeps me interested in those is his literal voice and the way he tells the stories aloud; I haven’t thought as highly of the written versions of some of his stories.)
3. I should’ve noted that I was distracted and/or sleepy during most of my reading of those chapters.
4. One other thing that engenders reader trust is having a whole book in their hands, especially one that has back-cover blurbs from people they already trust. So I’m always a little wary of my own reactions to manuscripts, if they’re the sort of reactions I might not have to the same words in a published book.