I tell people I only read short books. I tell myself I only read short books.
When a friend published a book and apologetically said "But it's not much of a book--it's less than 200 pages," I had to reply "That's the best kind! It's the kind of book that people will actually read!"
When asked about my favorite books, I can cite a whole list of really great reads under 200 pages long. The books in the Boston Review series qualify, and as a bonus, some add on scholarly comments, such as Susan Moller Okin's Is Multiculturalism Bad for Women?. Loren Graham's What Have We Learned about Science and Technology from the Russian Experience? is a favorite of mine, not just for its fascinating thesis, but primarily because it is the perfect model of a short book. It asks some clear questions and then provides evidence to answer each. The evidence and the interpretations of it are not always the obvious ones.
Lectures can make good short books. Austin's How to Do Things With Words just would not have been as good a read if it were three times as long. I've never read Robert Brandom's Making It Explicit, which is over 700 pages long, as though he had to make it all explicit. And I don't believe everyone who says they've read it. It's far more believable that they might have read his Articulating Reasons, published just a few years later and covering similar territory in just over 200 pages.
But these books are (analytic) philosophy--and perhaps philosophy ought to be brief. But no, when I think of my favorite novels, they too are short. To take one example, Christa Wolf's Cassandra is less than 150 pages. And far more than novels, I always love to read a short story by Alice Munro or Muriel Spark.
In spite of my long-standing penchant for quick, concise reads and common, straightforward language (spare me the neologisms!), I've found myself reading long books this summer. But by necessity, only a few of them: Bowling Alone (544 pages), The Poisonwood Bible (576 pages), Roads to Quoz (592 pages).
From earlier this year, here's a column by historian Ann Vileisis on "The Pleasures of a Big Fat Book" (ooooh! Look at her bookshelf! That's like my bookshelf--well, it would be if you removed the big fat Russian novels!)
What's your preference? The focus of a short book or the rambling development of a long one? Is a preference for short books conditioned by too much Internet reading and too little patience?