It's not enough to write a book any more. Now you have to write a proposal to get the book under contract, a grant application to get funding, another grant application to get funding (rinse and repeat as necessary), a report for your department on what you've done this year, and what you plan to do next year... and now your publisher is asking for chapter abstracts and keywords when you send the final manuscript in for editing.
"Have you had any push-back from authors?" our manager asked. Well, no. They're used to writing about what they've written about—not that it's necessarily enjoyable, or valued. But the reflexivity of that activity (writing about what you're writing about) isn't just a cute way of stating the obvious, it reveals a bit of a truth about writing: the object of the writing (the research, the story) and the writing itself aren't easily separable. You're always trying to tell the story, you're always inevitably condensing and narrating and leaving out and framing and filtering. Whether you're giving your elevator pitch ("You'll love it; it's about this early modern German named Hermann Connring and the fundamental shift in the relationship of past and present.") or writing an 800-page manuscript, or editing that manuscript down to a reasonable 120,000 words, or even distilling that manuscript into a 7-line table of contents (Germans, by the way, call it a "table of content"—that little change always reminds me that there must be substance to the book.), it's always a representation. The only sharp line in representation is between the representations and reality.
And so, no, we don't get push-back. Maybe grumbling about another task to do, but hey, we've been adding to authors' tasks to do ever since we took away their typists (well, most of their typists) thirty years ago. (The division of labor giveth, and the division of labor taketh away.) We still overexplain the need; we throw around words like "mixed media environment," "searchability," and "discoverability," but fundamentally, we're asking for a map.
And so I write: You’ve already created one map of your book: the table of contents. The table of contents is a large-scale “highway map” of the general route that your readers will take. There will soon be another map in the form of an index; this is a very local map (“Where was that excellent taco restaurant? Come to think of it, where are all the taco restaurants? This guy did a wildebeest-shooting helicopter ride but I want to do a cross-country taco hop.”). The abstracts and keywords are yet a third kind of map: they’re like the maps posted on signs at the entrance to a campus, with a “you are here” to situate the visitor, and to show that reader, who may not have come in the main entrance, what there is to see. Publishing now involves searching and coming at books (and chunks—that's a technical term—of books) from all sorts of directions, and so you can't rely (if you ever could) on a reader looking at the Table of Contents and the Introduction.
But it's all representation, and it's What Authors Do.
*Thanks to J.Z. Smith for my title phrase.