We've talked before about the book as a cross-technological concept -- that a "book" can mean either (or both) a codex or a scroll, an electronic or a physical unit. Roughly speaking, our ideas of what a book is are driven by the different technologies attached to reading -- but there's also SOME sense in which "book" persists across or transcends any particular technology. AND book can be an exclusive concept -- we can say, "that's not a book, it's just a pamphlet," or "that's not a book, it's just a collection of odds and ends," or "that's not a book, it's a dictionary," etc. (We can also use it ironically; in the police procedural The Wire, a detective jokes to a suspect, "I'm looking at your sheet... Man, you can't even call it a sheet, it's more like a book!")

AND books aren't unique in this; the word "movie" functions much the same way, whether we're talking about a DVD or a trip to the theater. TV shows and commercials are technically "movies," but we don't think about them this way.

The necessary criteria for something to be called a "book" is usually 1) length and 2) unity. If a written text is too short or too long, or is too heterogeneous or not self-contained, then we might start calling it something other than a book -- a volume in a series, maybe, or a collection, a pamphlet or booklet, an entry or article.

But how long is long enough? How unified does something need to be? Where do our assumptions about this come from?

This appears to be where we fall back again on technology -- or, rather, reader expectations as partly determined by technological limitations, economic choices, and social realities. At least, that's what this post by Charlie Stross suggests -- Why books are the length they are. Stross looks at science-fiction books (mostly mass-market paperbacks) from midcentury to the present -- this is what he finds:

One account I've heard (from an editor who was active throughout this period) is that it was the distributors. The mass market for paperbacks prior to 1991 was dominated by wholesalers who supplied retail stores — not bookshops, but local supermarkets with wire-mesh book racks. The wholesalers knew their markets intimately, and would match mass-market titles to the supermarket customers on the basis of their clientelle — SF/F was popular near technical schools, for example. When the inflation of the 1970s and 1980s forced publishers to raise their cover prices, the distributors pushed back and demanded that if the product cost more, it had to be bigger — not taller or wider, else it wouldn't fit the racks, but fatter. (They were, after all, primarily in the grocery business rather than the book trade. You want to charge more for that lettuce? It better be bigger!)

Once a trend like that becomes established, it's hard to stop. Put yourself in the position of a bored browser in front of a supermarket wire-rack, contemplating novels by two authors you've never read. They both cost the same, and you have enough pocket money to buy one. The year is 1980; LibraryThing or other internet resources aren't available. How do you make your mind up? Well, you remember what you've heard about the authors, and you look at the cover painting, and you read the back flap blurb. Assuming all of these are equal ... you probably buy on weight, because you subconsciously anticipate a longer reading experience and, all things considered, good experiences that last longer are better than short ones. Remember that the actual cost of the paper and ink is only a small component of the retail price of a book — around 10-15%. Increasing a book block's size from 150 pages to 180 pages is cheap. And so, from the 1960s to the 1990s, publishers unconsciously trained readers to expect longer novels.

Hardcovers pose a different problem, all but guaranteeing that long, single-volume hardcover books would be solely the province of what Stross calls "Epic Fantasy" (e.g., the single-volume editions of The Lord of the Rings):

In the UK, all retail fiction books (paperback and hardcover alike — aside from some special high-quality editions) are perfect-bound. Pages are printed and collated, guillotined to form book blocks, then bound into the cover using thermosetting glue. There's no obvious limit to the number of pages you can bind this way other than the reader's wrists and the flexibility of the glue — some 1970s paperbacks were notorious for disintegrating on first reading, but these days perfect-bound books up to 1400 pages aren't really unusual ... although midlist authors are not encouraged to go there: production costs scale with the size of the book, and you don't get to charge twice as much money for an 800 page novel as you would for a 400 page book.

In the USA, paperbacks are perfect-bound, but hardcovers are still frequently bound as groups of signatures (blocks of 16, 24, or 32 pages), which are stitched into a cloth binding. It's a higher quality technique, but it seems to be a bit less forgiving of large bundles of pages. In particular, I am told by my editors at more than one publisher that if the page count in a US hardcover goes over roughly 424 pages, this causes no end of problems: they have to outsource the binding to a bindery that uses a more expensive technique, disproportionately raising the production cost of the book.

Finally, Stross speculates on some of the implications of this history for digital reading:

[I]f we make a successful transition to ebooks — that is: if ebooks become a major sales channel and authors are still writing professional quality work for money, and readers are finding some way to pay them — we may see a revival of other formats: novellas for one (they're undergoing a renaissance in SF publishing among the smaller publishers), the Dickensian serial for another, and the gigantic shoebox-sized monster for a third. The corsetting of the modern novel to fit between the tight constraints of binding costs and price elasticity of demand will be unstrung, or replaced by bras, or some other over-stressed metaphorical construct.

What I love about this account above all is the complex dialectic between the inherent technical limitations of a particular technology (or complex of technologies) of production, presentation, and storage on the one hand, and the psychological/sociological expectations of readers on the other. It's never (well, hardly ever) just one or the other, JUST technology/economics or JUST ideology/culture. It's almost always a complex of both.

Let's go back to Richard Curtis's comparison of the ABC/Cablevision dust-up with publishers' attempts to wrangle their readers' expectations about the pricing and availability of e-books:

The moral of Cable­vi­sion vs. ABC as far as the pub­lish­ing indus­try is con­cerned is that con­sumers have no patience for such arcane issues as win­dow­ing, loss leader pric­ing or agency busi­ness mod­els. They expect their book when they hit Down­load and they want it at a rea­son­able price. Edu­ca­tional ini­tia­tives are a waste of time. We need to get our pric­ing act together. Though there is no Acad­emy Awards show to bring us to the brink of cat­a­stro­phe, the e-book indus­try will not real­ize its full poten­tial until we pro­vide our prod­ucts reli­ably and at prices that make sense to customers.

Publishers and retailers of mass-market sci-fi didn't try to reach out and educate their readers about the inherent costs and limitations of a perfect-bound paperback. They just told their authors/editors to make the books about 300 pages long, slapped a picture of a dragon on the cover, and charged $3-$5 for each book. And for decades, that worked.

There's no reason to assume that this wouldn't work for a digital format, either. Think about iPhone apps: they virtually all cost somewhere between $0 and $10. In a very few cases, you might carefully research an app, but for the most part, they're impulse purchases -- the digital/mobile equivalent of the mass-market book or magazine we snatch up at the supermarket. Clear expectations and evolving standards make a successful marketplace. Could it be that simple? (Maybe -- only because this idea turns out not to be so simple at all.)