Towards A World of Smaller Books — Crooked Timber:
I think you can push this argument further. I would estimate that about 80% of the non-academic non-fiction books that I do not find a complete waste of time (i.e. good books in politics, economics etc – I can’t speak to genres that I don’t know) are at least twice as long as they should be. They make an interesting point, and then they make it again, and again, padding it out with some quasi-relevant examples, and tacking on a conclusion about What It All Means which the author clearly doesn’t believe herself. The length of the average book reflects the economics of the print trade and educated guesses as to what book-buyers will actually pay for, much more than it does the actual intellectual content of the book itself.