Rachel Toor in the Chronicle:
What really happens when a scholarly book is published?
The author is sent 10 copies, which he gives to close friends. Sometimes her family will take her out for dinner. Maybe a generous colleague will host a potluck. Rarely, a bookstore where the author is a loyal customer will let him read to a handful of students who would like, but can't afford, to buy copies. And then? Nothing.
All you can realistically hope for—but not count on—is that the book will eventually—and this could take months or years—be reviewed in an academic journal. Book reviews are, therefore, important to authors. But who else should care about those reviews? And why should any faculty members, buried under their own work, bother to write one?
It's not for the money. As with other aspects of our peculiar profession, the remuneration for this kind of intellectual labor will not buy you a cup of coffee.
It's not for the recognition. Only those with a specific interest in the field are likely to see the review; you can't impress the other parents in your kid's playgroup, or expect your mother to happen on it by chance.
And it's not for the sake of beefing up your CV. While many people do use reviews as padding, they don't "count" for much in the hiring, tenure, and promotion process.
So why bother to write one?
Because we are expected to do service to the profession. Because we are invested in our fields and want to be involved in a conversation about where they should go. Because it's nice to get a free copy of a book that you are going to want to read anyway, and then be forced to think hard about it....
However:
If the current climate in publishing and academe requires that scholars be ambitious and accessible, that they write clearly (if not simply) for more than the 15 people in a sub-sub-subfield, then professors will have an opportunity to become engaged in American cultural, social, and political life in meaningful ways. The monograph and book-review sausage factories are not, I think, the best use of our collective cerebral resources. It's better to write one good article than to review 20 books, and even better to write one good book.
It seems like there is a disconnect in that paragraph, at least in economics. I don't think that writing clearly (if not simply) for more than the 15 people leads one to writing a journal article. That sounds more like blogging. And, in what academic field is the marginal rate of technical substitution 1 good journal article for 20 book reviews? Or, by transitivity, 1 good journal article for 1 book?